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: 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)
Goodbye, Farewell, and Amen - S11-E16
Factual error: When Hawkeye leaves the tank after parking it in the trash heap, he comes out of the cupola hatch. He should be coming out of the driver's hatch, because he sure as hell didn't drive that tank from the turret.
Answer: Even an Army field hospital would have SOME weapons for self-defense if the enemy attacked. What's meant is that it's not a combat outfit, and therefore wouldn't have enough weapons to actually attack anyone. (It's also mentioned a few times that the Officer of the Watch is supposed to carry a pistol at all times, but Hawkeye refuses to do it when he's in charge and Colonels Blake and Potter don't enforce the rule).
Captain Defenestrator