Factual error: In surgery Trapper John is singing Frank Sinatra's version of "I got you under my skin". Although it was written in 1936, Sinatra did not release it until 1956, after the Korean War ended. The 1936 version sung by Al Bowlly sounds nothing like the version Trapper John was singing, which was mimicking Sinatra's version.
Suggested correction: While it hadn't been released on vinyl until 1956, Sinatra had sung the song as early as 1946 on his radio show and during live shows.
The version Frank Sinatra sang on his radio show was similar to the original version used in the movie "Born to Dance" (a movie he references before singing his two songs). He didn't change it to the big band version that Trapper imitates until 1956.
Factual error: When Klinger's walking with Captain Allen and the Stars and Stripes photographer, just before their introductions to "Ben" they pass an empty corrugated box with its flap open, and the recycling symbol can be seen on the flap. Recycling symbols were not in use until about 20 years later.
For the Good of the Outfit - S2-E4
Factual error: During Henry Blake's command, a model of a Bell UH-1 'Huey' can be seen hanging from the ceiling of the commander's office in several shots. In fact, the Huey's first flight was only in 1956.
Factual error: Radar gives the location of the battle as Longitude 70, Latitude 27. This means the Korean war has spread to India. (00:21:00)
Factual error: The announcer says that it will be the 53rd Army-Navy game, but the game has been played every year since 1890, with no games in the years 1894-98, 1909, 1917-18, and 1928-29, so this game would be number 51. Additionally, at the end of the episode we find out the result was Navy 42 - Army 36. While Navy won all three games during the Korean conflict, none of those games ended with such a score. The score in the 1950 game was 14-2.
Factual error: While on the phone, Radar spells out BJ's father-in-law's last name, "H-A-Y-D-E-N" to which Hawkeye quips, "M-O-U-S-E" parodying the old line from the Mickey Mouse club. The M.M. club didn't air until 1955.
Factual error: When Radar, Hawkeye, and BJ find the letter from cpl. Benson to I Corps, Radar says that cpl. Benson's been here since June. Later in the episode when col. Potter, Radar, Hawkeye and BJ confront Benson, Benson says he is there on orders of a colonel who did not get treated quickly enough. Potter says he remembers this colonel was there a couple of months back. BUT, this episode of M*A*S*H takes place during Kentucky Derby Day. The Kentucky Derby has always been held the first Saturday in May. So, if Benson has only been at the 4077th for two months, and he arrived in June, then this episode should be taking place in August, not May.
Springtime - S3-E6
Factual error: Radar mentions to a nurse he's smitten with that the movie that night is "Firstborn of Godzilla." Godzilla (the movie, not the monster) wasn't released until 1954. (00:15:10)
Goodbye, Farewell, and Amen - S11-E16
Factual error: In "Goodbye, Farewell and Amen", the shot of the helicopter pilot's hands show him wearing Nomex flight gloves. These were not used until 1967 in Vietnam. Black leather flying gloves were used during the Korean war.
Factual error: In one episode in the hospital tent, Hawkeye hands a Hershey Chocolate Bar to a wounded soldier lying in bed. The back of the candy bar had a Universal Product Code (UPC) on it. UPCs were not used until the 1970s.
Baby, It's Cold Outside - S7-E9
Factual error: While watching the Sonja Henie movie "Sun Valley Serenade" Colonel Potter says at one point of the movie "This is supposed to be where she does a triple axel and ends up in a split." Then he has to leave and says "Now I'll never get to see it." He wouldn't be able to see it until 1989 when Midori Ito from Japan was the first woman to complete a triple axel in competition, Tonya Harding was the 2nd woman to complete one and the only American woman. And I doubt Sonja Henie ever did anything as complicated as a triple axel even with her 3 Olympic Gold Medals.
Factual error: Amongst Radar's comics are several not published until after the end of the Korean War, including issues of The Avengers and Spider Man.
The Abduction of Margaret Houlihan - S5-E6
Factual error: When Col. Flagg makes everybody close their eyes when he leaves, you hear the sound of glass shattering, but the window was a thick sheet of plastic.
Factual error: During this episode, Sergent Klinger gives a Hershey Chocolate Bar with Almonds (although the 'Hershey' name is obliterated on the bulk box as well as the bar itself, there is no doubt as to what it is) to a wounded North Korean soldier, who accepts it and turns it upside down, revealing a Universal Product Code bar code. Bar codes were not used on products until some 20 years later. (00:12:20)
Factual error: After the opening credits it cuts to Klinger at Mail Call, and Father Mulcahy's reading Ring Magazine which is dated December 1969, 16 years after the Korean War ended.
Factual error: Henry says that every Wednesday, his wife drives up Route 26 with some friends. US. Route 26 starts out in Nebraska and leads to Oregon. The closest thing that could be described as a "Route 26" would be the road leading from Princeton, IL to Dixon, IL which begins 85 miles from Bloomington. The writer probably meant Route 24, which passes about 20 miles north of Bloomington. (00:03:10)
Factual error: Radar impersonates John Wayne, playing a scene from McLintock - a film which was not released until 1963, which was 10 years after the end of the Korean war.
Factual error: Hawkeye and Trapper are concerned about the theft of a stock of hydrocortisone, but that drug wasn't introduced by the FDA until 1952.
Factual error: When BJ and Hawkeye go to Potter to talk about Cho Lin wanting to get married at the 4077th, Potter mentions he expects to be home in Nebraska in 16 months, three weeks and four days when they try to fool Potter about Cho Lin. Potter has always said he and his family live in Missouri, however.