Brian,
It may be possible to date the manufacture of your Luger within a couple of years. Please refer to these discussions:
http://forum.lugerforum.com/showthre...ght=frame+spur
http://forum.lugerforum.com/showthre...ght=frame+spur
http://forum.lugerforum.com/showthre...0667#post30667
and report whether your Luger has a straight or spurred recoil spring well; a reinforced or unreinforced frame; and an unrelieved or relieved sear bar. Your observations will help narrow down the time frame.
--Dwight