Factual error: In several episodes, German hand grenades, the famous "potato mashers" are seen. In (almost) all cases the Stielhandgranate 43, easily identified by its pull pin through the base of the head, was used. If the series is set in 42, the grenades should be the 24 or the 39 model, because the Stielhandgranate 43 - as the name suggests - was introduced in 1943 and didn't see widespread deployment until 1944. The earlier models didn't have a pull pin but used a pull cord that ran through the handle and was hidden by a screw cap at the end.
Visible crew/equipment: As the two German officers come out of Klink's office and approach the radar truck after Kinch leaves, the shadow of the cameraman, the camera, and the camera tripod are plainly visible on the left side of the scene on the ground.
Man's Best Friend Is Not His Dog - S4-E6
Continuity mistake: The dog LeBeau is holding shifts position on his arm with each camera change.
Man's Best Friend Is Not His Dog - S4-E6
Other mistake: When seeing the tanks through the viewfinder, Carter's hands and the background are frozen, and the tanks are actually a clip of a wartime newsreel.
Factual error: Throughout the show, German officers talk about "Nazi" this, "Nazi" that, even in official capacity. In fact, the mere mention of the diminutive "Nazi" could get you in serious hot water for the disrespect and dissent it implied. Correct would be either "National Socialist" or some reference to the Reich: e.g. "Officer of the Third Reich" instead of "Nazi officer."
Kommandant of the Year - S1-E3
Continuity mistake: The missile sitting on the trailer is thin and yellow, the missile actually seen flying is a fat, pointy, silver Atlas missile - which is an American intercontinental missile by the way, not a German tactical missile.
The Kamikazes Are Coming - S6-E20
Continuity mistake: When Otto and the Russian go to leave there's another man with a blue hat by the door. When the angle changes, there's suddenly a German guard standing behind him.
The Sergeant's Analyst - S5-E23
Factual error: In this episode, the running gag is that Schultz keeps flattening Col. Hogan's pumpernickel loaves. In reality, pumpernickel is a very compact bread that contains virtually no air at all and is impossible to flatten in this way. The shape is also wrong: pumpernickel is almost always baked in rectangular baking pans. To avoid confusion: the original, German pumpernickel is quite different from what's sometimes referred to as pumpernickel in England and America.
Factual error: When the safe doors blow, we have another case of a fuse still burning after the charge blows. Since the charge blows when the fuse is burnt up, that's literally impossible. (00:20:00)
Factual error: Klink usually wears an EK1 (EK= Eisernes Kreuz = Iron Cross first/second class) chest cross with a WW1 EK1 repeat badge, but he neither wears an EK2 ribbon nor a WW1 EK2 repeat badge. This is not a legal combination, he either has to wear both or none at all. The EK1 and EK2 repeat badges were awarded to soldiers who were awarded an EK1 in WW1 and another in WW2. To be awarded an EK1, you had to have the EK2 already. The Legal combinations would be: EK2 ribbon in the button hole with or without EK1 chest cross, EK2 ribbon in the button hole with repeat badge with or without EK1 chest cross, again with or without repeat badge. One legal way of wearing it is seen in S5E3, "The Klink Commandos", where Hogan wears a black-and-white WW1 EK2 ribbon with repeat badge and an EK1 chest cross with repeat badge. It doesn't make any sense for him to wear that (separate mistake), but the way of wearing it is correct.
Continuity mistake: When Klink is "taken hostage" in the barracks, he is in his tunic only. Later in the car he has his overcoat on. He was supposed to be kidnapped, he could hardly ask Hogan to let him slip into his office for his coat.
Factual error: During the show, many (not to say most) higher officers are seen wearing a Knight's Cross with Crossed Swords and Oak Leaves, the fourth highest award for military valor of the Third Reich. In fact, a total of 177 of this and higher-ranking medals were awarded during the entire war, most of them in '43 and after. The series is allegedly set mostly in '42. Historically correct, most Knight's crosses should be of base rank or with oak leaves only, as of these categories more than 8000 were presented.
The Rise and Fall of Sergeant Schultz - S2-E6
Factual error: General Kamler awards Schultz what he calls "The Iron Cross Fourth Grade." There never was a version of the Iron cross called that. The Iron cross came in two ranks, called 2nd class ("zweiter Klasse") and 1st class ("erster Klasse"). The ranks higher than that were called the Knight's Cross ("Ritterkreuz des Eisernen Kreuzes") and were never pinned to the chest but worn around the neck.
Drums Along the Dusseldorf - S3-E30
Factual error: All through this episode, characters keep referring to the river the bridge *du jour* spans as "The Düsseldorf" or "Düsseldorf river." The city of Düsseldorf is situated on the river Rhine - there is no "Düsseldorf river." It's a well known fact that the producers were hardly geography whizzes, but not knowing the Rhine is bad even by their standards. Curiously enough, there kinda is a "Düsseldorf river" called the Düssel, and it meets the Rhine there. The Düssel however is a small streamlet that a well-trained man could probably jump over - so the mistake is still a valid one.
Everyone Has a Brother-in-Law - S2-E23
Factual error: Schulz repeatedly calls Klink's adjutant "Kapitän." In the German armed forces the rank Kapitän only exists in the Navy, the German equivalent for the American rank of Captain (which is obviously meant here) is Hauptmann or Stabshauptmann.
Reservations Are Required - S1-E15
Character mistake: In this episode, Hogan suggests a helicopter as means for escape from Stalag 13. As a matter of fact, the allies had no helicopters operational before April 1944. The famous R-4 made its first flight only in January 1942. So unless Hogan planned to steal one of the Luftwaffe's 20 FW Drache (a maximum of ten or so existing at any given time) or a whole bunch of the single-seat Flettner Kolibri (24 total built) he was out of luck.
Anchors Aweigh, Men of Stalag 13 - S1-E16
Character mistake: Klink claims that the North Sea is about sixty miles from Stalag 13, in reality however the town of Hammelburg and thus the nearby camp are about three-hundred miles from the North Sea.
Other mistake: Towards the end, the shot of the plane landing is a recycled shot. Even though Klink waved the flashlight, an unidentified person can be seen in the shot waving a signal light in the midst of the field. Klink was by his car.
Continuity mistake: In Hogan's quarters, as he and Critendon are talking, his arms are by his sides, and suddenly crossed. As Hogan goes to get his hat off Critendon's sword, his right hand is shown, then after the angle changes, his left hand draws back with the hat, and his right comes up to grab it.
Revealing mistake: When the homing bomb hits Burkhalter's car because Klink used the radio, you can see the mini tank from "Tanks for the Memory" (s2e9) sticking out of the wreckage.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.