Peace on Us - S7-E2
Visible crew/equipment: When Radar gets off the phone with the guard at Panmunjom and tells Colonel Potter and BJ that Hawkeye's gone on ahead, at the start of the next shot we can see the back of the soundstage set at the top, right side of the screen. And notice that Hawkeye's and the guards' voices are echoey on the soundstage in this shot.
Answer: The C-42 was a military variant of the Douglas DC-2. Very few C-42's were built, so it's questionable that Potter would specifically have seen that particular model, but, given his military background, it's not entirely unreasonable that he might use the military designation even when the aircraft in question is actually a civilian DC-2.
Tailkinker ★