Frame Identification Help

[plano_harry]

I am trying to sort out my Luger. I now understand that I apparently have a fully matching upper from a 1921 Weimar era DWM. I could use help with the frame since it has no date and no acceptance proofs that I can identify. I have tried searching the forum for unproofed frames, but didn't find anything that seemed to fit. The only thing I have to go on is the frame serial number"2166" + script "s". Is this a '37-'38 Mauser frame? In addition to the full side views, here are pics of every mark that I could find on the frame. Thanks in advance for your help! This was a historically legit WW2 bring back, not a recent marriage.