What I'd like to know:
Did this start its life as a military or commercial pistol?
yes
What history is able to be traced from its markings (origin, possible military use, possible Russian capture, East German use, etc?)
Imperial German military for sure, RC ?, EG rework with correct proofing, Vopo use-yes
Identification of the various stamps (somebody's probably gonna tell me "buy a book"....which one?)
Check the stickys for explanation of the original proofing, Ed and I have answered the others-I think
What is the "round" stamp near the takedown lever?
looks like a cancelled Vopo sunburst
Anything particularly interesting/unique about this Luger?
Maybe -need more picts!
Congrats on your second luger - a nice "Vopo"!
Do the mags match the pistol? What are the markings on the bottom of the barrel near the receiver? Import markings?
More views of the pistol markings are needed to discern additional details.
Welcome back, don't wait ten years for another luger!