The vehicle used to represent the German Tiger tank is actually a U.S. built M7 self-propelled howitzer. The M7 dates to World War II.
In the opening scene Klink is bragging of Third Reich successes, the prisoners are muttering, and Newkirk clearly says, "rhubarb rhubarb". That is sort of an actor's in joke. In the early days of British radio, TV, and movies, crowd muttering scenes often had the extras repeating "rhubarb", "peas and carrots" or other nonsense words to simulate background dialogue.
This is one of the few early episodes in which LeBeau wears a blue sweater. For the rest of the series his sweater is red.
During the ending credits of this episode there is an extra bar of music while Werner Klemperer and John Banner names are shown. Also true of the next episode, Kommandant of the Year, and perhaps others but this is not typical.