That's No Lady, That's My Spy - S6-E17
Other mistake: The Kommandant's building and the barracks appear to be only twenty to twenty-five feet apart, showing that this scene of Roll Call is in the studio. Otherwise, the outdoor shots are at the studio back lot.
That's No Lady, That's My Spy - S6-E17
Factual error: Hogan tells Carter that the bush he's camouflaging himself with is poison ivy. Poison ivy is not native to Germany, the very few wild plants that exist today descend from those introduced to botanical parks after 1942.
That's No Lady, That's My Spy - S6-E17
Revealing mistake: When the men are in ranks for roll call, it's snowing heavily. Given the pitch of the barracks' roofs, there shouldn't be any snow sticking. Therefore, if looked at closely, it can be seen that the "snow" on the roofs is painted in place.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.