Looky here:
https://www.gunbroker.com/item/769324647
Seller describes it as "Unusual 1933 Mauser Police Luger Rig in 9mm". Could have been.
What I think I'm seeing is an unusual East German re-build. Pay especial attention serial numbers placement and size of font. Also look closely at holster marking.
IMO, this is a gun with more than one story to tell.
Kyrie