It's Not Easy Being Green - S5-E16
Factual error: Boomhauer's car, Ms. Sally, has a Texas flag license plate on it. These plates were not issued until 1992, but Ms. Sally was driven into the quarry in the late 70's or early 80's.
When Cotton Comes Marching Home - S5-E5
Continuity mistake: When Cotton is trying to use the circular saw on the car dealer, the extension plug it's connected to gets disconnected around half way onto the alley road. The next shot its moved to just past the driveway, and the following shot it's now moved to about halfway down the driveway.
Hank and the Great Glass Elevator - S5-E11
Continuity mistake: When Hank & the guys are talking about mooning from the glass elevator, Hank is positioned with his back next to the wall as he is sitting at the table. When Dale says his high school mooning was the best thing he ever did it. It then shows Hank and he says, "The vice principal gave you a week's detention" and is now sitting away from the wall with his back to a group of men in the opposite table.
Continuity mistake: In the episode where porn videos are being sent to Hank, there is a close-up shot of a machine printing out address labels for Hank's house. These labels say 320 Rainey Street. However, in this episode, when Peggy is looking at the mail, all of their mail has 84 Rainey Street as their address. In several other episodes, the address is stated to be 123 Rainey Street.
Plot hole: After the old guys take Hank's clothes & throw him over the fence at the Alamo, Hank goes right into the building without having to unlock the door. Despite the fence being locked up, it seems a little odd that such an historical monument like the Alamo wouldn't have its main door locked.
Peggy Makes the Big Leagues - S5-E4
Continuity mistake: When Peggy writes on the board in her algebra class she writes a2= b2 + c2, around the middle of the board. Whilst talking to David the writing moves to near the top left of the board.
Continuity mistake: When Allabaster is chasing Hank in his car, he loses the front left hubcap from his car. Just as they go over the speed bump if you look at Allabaster's car when it is in the air for a brief second you can see the hubcap is back on the tyre (more visible in slow motion). Later we see the tyre again and the hubcap is off for the rest of the scene.
Deliberate mistake: When Dale calls Hank from John Redcorn's trailer, the wooden clock behind Hank (in the Hill's kitchen) has no markings or hands to tell what time it is. This is a mistake as it is the exact same shape and object as it was before this episode and I doubt they replaced the clock with an completely exact object as before. A side note on the mistake is that it may be considered deliberate as the clock in previous episodes is shown frequently in the background and will generally change between shots.
Peggy Makes the Big Leagues - S5-E4
Continuity mistake: On Peggy's first day of teaching she is called over to the lunch table of some of the other teachers. Other than the woman she first talks to, most of the people at the table keep changing. The first shot is a wide shot of the group of people at the table with the second shot a close up shot of them. Firstly the guy across from her at the table is wearing a green shirt. When she sits down its now a white shirt. The other mistakes is with two of the other people. At the end of the table there is a black guy and the lady in the middle is wearing a dark jacket with black hair. When Peggy sits down the black guy is now white and the woman in the middle is now very old with glasses, white hair and a light purple top.
Continuity mistake: Whilst Bobby is trying out for the mascot position of the Landry Longhorns, they have a tape player on the judge's desk for the music. In the end of Bobby's tryout there is a shot from behind the desk and the tape player has disappeared.
Continuity mistake: When Peggy & Hank are talking about Tammy whilst in bed, there is an outside shot of the house with light streaming out of one of the windows (the master bedroom). Yet when we see Peggy & Hank inside their room the blind for that window is down, making it impossible for the light to stream out of the window like it does.
Continuity mistake: As Hank is telling Bobby to give his speech at Thanksgiving everyone moves in around Bobby. If you look at Bill he comes in from the right even though he was on the standing to the left of Bobby in the previous shot.
Other mistake: When Hank runs into the building to hide and lays down in the square of moonlight on the floor, he looks up at the window and a couple of clouds pass by. The clouds move too quickly, and when Hank is shown again, no shadows from the clouds move across him.
Continuity mistake: In the scene where the mechanic is checking Hank's car, there is a guy in the car who is sitting on the right side with his hands on the wheel. The problem is the steering wheel is on the left side of the car. In the next shot the steering wheel and the guy return back to the left side of the truck.
Continuity mistake: Whilst Hank is talking about the price of popcorn at the movies Bobby & Connie come up to Hank and there is a blue poster next to Bobby of a woman holding a gun. In the next shot you can see the blue poster is now next to Hank despite a red & orange poster next to Hank in the previous shot of him.
Continuity mistake: When Hank & Peggy are discussing what film to see, Connie & Bobby were to the right of Peggy who is right next to the truck. In the next shot Hank & Peggy are getting in the truck and Bobby and Connie are already there. Yet we would have had to have seen them go behind or in front of Peggy to get into the truck.
Deliberate mistake: As Dale is taking photos of Bobby's ventriloquist doll you can see he is taking the photo from the upper right of where Bobby is standing in his house. However the angle of which he takes the photo from would be impossible as it's to the left of their screen doors and there is no window or see-through material from that angle.
Continuity mistake: At the start of the episode when Hank gives Bobby the turkey knife it is in a red padding. Just as he's about to carve the bread (for practice) the padding is now yellow and stays that color for the rest of the scene.
Continuity mistake: During the scene where Bobby is accusing Hank for the first time of taking Native American land you can see Bill is standing behind Bobby. In a close up shot of Bobby, Bill is now standing to his right. As Bobby starts walking Bill is behind him again.
Continuity mistake: Whilst the old man in the retirement home is about to give Bobby the ventriloquist doll, there is a shot of just Bobby. In this shot you can see the jacket and hat on the coat rock and the coat is on the top rack. When we see both of them together the coat rack has another rack above the jacket now.
Answer: Jeffrey Boomhauer is a Texas Ranger as can be seen in the final episode at the end when he sets his wallet down, it flips open revealing a Texas Ranger badge.