Continuity mistake: When the pit boss is taking the rolled up 5 containing the pair of dice out of his pocket, his fingers are hiding the end toward Mulcahy. When the camera angle changes, the fingers are moved so Mulcahy can see the hidden dice.
Revealing mistake: During the melee at Rosie's, after Klinger gets his money and jewelry back from the cheats a guy is thrown through windows, and though we hear the sound of smashing glass we see the shreds of plastic fluttering.
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 ★