Klink's trademark monocle is missing in the last scene.
When Hogan first steals Klink's staff car, the luggage is still on the roof. Later, when the car is used, the luggage is not there. At the end, when Klink goes back to STALAG 13, the luggage is back. No mention on how it got removed and restored.
The first time Hogan visits Tiger in her cell, the body of the valve on the pipe outside Tiger's cell is painted a dull reddish brown. The plates that join the two halves of the valve have rounded corners, and are shaped like an American football with the ends chopped off. Later, when the fake Himmler bangs his head against the valve join plates, the valve body is silver, and the join plates are round.
Just as the fake Himmler is leaving Tiger's cell, while his back is to the camera, he looks up to spot the valve join plates to make sure he hits the padded part of the valve.