Character mistake: As Stauffen parts company with Col. Hogan at the road checkpoint, he salutes Hogan. While that is understandable under the circumstances - after all Hogan just saved his life, it would also be highly suspicious. Both Schultz and Stauffen's adjutant were watching them, so it can't be said they did it surreptitiously either. After all, Stauffen is a German general whereas Hogan is an allied prisoner officer of inferior rank. For an officer of higher rank to initiate the salute is a demonstration of great respect and/or thanks, which, as far as anyone besides Stauffen and Hogan knew, was not warranted in this situation.
Other mistake: When the General arrives at Camp 13 and is greeted by Klink, he notices Hogan and ask Klink who he is. Klink only says he's the Senior POW, the General sends his Aide to get Hogan. The Aide addresses Hogan by name, but Klink never said Hogan's name. (00:07:40)
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.