Werner Klemperer and John Banner worked together in the 1961 film "Operation Eichmann." Klemperer portrayed Adolf Eichmann and Banner played Rudolf Hoss.
General Burkhalter's staff car was actually an American hybrid with a Mercedes Benz logo on it. Col. Klink's staff car was a 1936 Mercedes 260D, although in some episodes it was the Pullman limousine model while in others it was the standard model.
The standard rifle of the German army in WW2 was the Mauser K98, but the rifle carried by Sgt. Hans Schultz (John Banner) and most of the other German guards at Luft Stalag 13 is actually a U.S. military issue Krag Jorgensen rifle. The Krag Jorgensen, used by the U.S. military in the early 1900s, was most likely substituted for the Mauser due to its abundant availability as cheap war surplus in the U.S. and its general resemblance to the Mauser rifle.
Throughout the series, all vehicles have Army license plates (WH, i. e. "Wehrmacht/Heer"). The vehicles from Stalag 13 should have Air Force license plates (WL, i. e. "Wehrmacht/Luftwaffe"), as it technically is an Air Force unit.
The RAF Corporal wears an incorrect cap. The cap he wears is a US style 'Garrison Cap'. He should be wearing a 'forage cap' whilst similar, has different shape and stitching. The garrison cap has 2 buttons on the front, which have been added to make it look like a forage cap. Garrison caps don't have buttons on the front.