Thanks for the excellent pictures, Ron!
Oh yeah, stock lug, I knew that ... as in rifle stock lug! (Very embarrassed!)
Somehow I was trying to turn that into the hole where the left stock/grip fits at the top. .
Anyway, my pictures don't show the stock lug as clearly as your picture so I just took my jeweler's Afga Lupe and there is no hole drilled at the top of the stock lug on either side. In your picture it sure looks like there's a hole drilled at the top of the lug.
So the frame is a WWII DWM! Thanks so much for that info. Didn't expect that.
Guess there's no way to figure out the year since the frame was separated from the receiver. And still there is no way to know when my Luger was pieced together other than sometime after the barrel and receiver were made in 1938. I bought the pistol in the early 1970s so somewhere in that 40 year period!
You guys are amazing, I've owned this Luger 30 years and read my books "The Luger Pistol", "Lugers At Random" and " The Luger Story" and never heard about the Mauser hump or hole! , but learned more about it in 24 hours than I have in in the years before!