Dwight, I just got off the phone with him. He says that the area under the safety has been milled out. He says it was nicely done but clearly not factory. The extractor is the only thing not sanitized and retains the proper markings.
When I asked him for some better pictures, he didn't sound like he was interested in taking any more pics, but would be happy to simply send it to me for inspection prior to purchase. If I didn't like what I saw I was free to send it back to him. I guess a fellow can't ask for any better than that...
He represents this gun as a solid shooter and that's all. The top numbers are all matching but different from the frame, though both are of Bulgarian origin. I'm guessing that this was a refurb done at an armory because he says the blueing is among the nicest he's seen on a Luger before. Although he doesn't claim anything like the kind of collection most of you all can boast of.
He sounds like a real nice guy and his trust in me is well placed. I'll give it a lookover and post you all some better pictures.
Dwight, thanks for the link. Looks like I'll doing some reading this evening...