Okay, if the barrel is not marked it may have been rebarrel later. does it have any serial numbers on parts? Any acceptance stamps on right reciever? Does it have a LETTER SUFFIX under the frame serial when viewed from the muzzle end, unloaded and lock open of course. When you say "no markings" does that include chamber date (I assume not) or Front toggle link. Serial numbers, type of magazine etc. Type of grips, straw parts, lots of things are important. See the id sheets in the technical section as a guide.This Luger has probably several eras of use and history. The shorter 30 Luger barrel and export marking make the commercial sales aspect the probable final type of use just prior to it coming to the US as a commercial gun I would think.
Click HERE for Luger Varation identifying sheets