Very Nice Luger, Congratulations!
I raised the question about the "WR" stamp a year and a half or so ago. It is a Mauser factory mark found on many pistols.
http://forum.lugerforum.com/showthread.php?t=23633
If you look over the parts on Lugers from DWM you see a variety of individual parts inspection stamps that can probably be tracked back to individual inspectors (within the factory, not WaAmt inspectors).
Bninning in 1938, to simplify Mauser quality control inspection, a single stamp was apparently used.
From Frank's post in response to my question:
"Marc, I did a bit of research on the "WR" Mark. In Sam Costanzo's Book "World of Lugers", page 219 he states:
"Quality control inspectors stamp found on bottom frame rail and also on middle toggle link." Found on 1938 through 1941 models."
Vlim also stated:
"Mauser was once officially called 'Waffenfabrik Mauser' (WM). In the 1920s it changed to 'Mauser-Werke A.G.' (MW). So a W and an M in the logo are to be expected."
"The WR / RW logo is often seen in areas that had been inspected for hardness. A popular explanation for the logo is 'Werksrivision', but it is also tempting that it refers to the Rockwell hardness test
"
It would be interesting if plant records from the 1938 timeframe could be found that indicate some kind of reorganization in the internal quality control apparatus at Mauser.
Marc