Reminds me of Top Secret...
... in that incoherent mixture of styles and fashions: 1960's haircuts, civilian clothes and Mercedes Benz, buildings from somewhere between the 50's and 70's, and, believe it or not, the old 1930's uniforms still in place. Is it reasonably believable that the thriumphant reich would have taken some time to update his style.
Somebody may answer about the hardships of predicting such a thing, but actual history gives us a strong hint: DDR military uniforms were actually taken for designs made for the Wehrmacht but never produced before war's end. So soldiers of an 1960's German Reich would have looked a lot like East German Soldiers of the same era. Why didn't anyone involved in the movie make such an obvious research?