A lot of 60 and 70 movies where made in places like Yugoslavaia and parts of Europe which liked (and needed) the money and still had lots of old WW2 kit.  Battlle of Britain & Von Ryans Express  - filmed in Spain. Israel the Big red One.   

Ok thats about saving money on a movie but sometimes reality is stranger than fiction. 

It's often held that Radar was a huge secret during WW2. Yet a wartime book published in 1943 called "Roof Over Britain " clearly discusses how this works (called radio location then) and this book was sold to the public. 

The new issue of Britan at War mag (#5) shows a german gun on a french chassis. 

Also it wasn't uncommon for german aircraft to be landed intact at british airfields - given RAF roundels and flown off for research. The germans also had some spitfires as well.

Pinky - you left the lens cap of your mind on again.