The newest it is, is 1945 and since it has DWM, and if original, then before 1935
Check and see if it has matching parts or mismatched, as I think a parts gun since its a commercial since it has so many parts with numbers. Which is normal for an army or police, but it has so many commercial marks.
The marking of 7,65mm - I would say it is from another country but then where
$400 is a very good buy for any working luger and jamming, well that could be the magazine, the ammo used, a lot of things.
Congrats!
Ed