Other mistake: When Henry is trying to convince Baker how wonderful the camp is, Henry says that they "had 'The Thing' and 'The Blob' both in one week." The movie "The Blob" was made in 1958. This season of M*A*S*H is set in 1951 and 1952 (and the war ended in 1953). (00:03:55)
Other mistake: During this episode, Trapper and Hawkeye keep switching Frank's pistol with other things. When Frank's training his South Korean platoon, Trapper, Hawkeye, and Radar show up all decked out, and while Hawkeye's telling Frank that using the anti-aircraft gun on the compound will draw enemy planes, etc., there's a pistol in Frank's holster. When Frank turns around, we see that Trapper's right arm is bent over his fly swatter the entire time until he steps away from Frank, and when Frank draws from the holster what he believes is the pistol, he pulls out a plunger, and although it's funny, Trapper never actually had the opportunity to switch the pistol with the plunger, nor did Hawkeye or Radar.
Other mistake: When Hawkeye and Trapper are arguing with Henry about not sending the little boy to the orphanage, Henry says, "Look, you think I wanna send this little fella away? I got two kids of my own. I'm a former child myself," but at the end of season 1 Henry's wife delivered a boy, whom Henry was aching to be with, so Henry really has three kids.