New Luger. Can someone help tell me what I found?

[DonVoigt]

Originally Posted by Iannn

Ok I think I found the proof marks on the barrel. Kinda hard to see with the naked eye but zoomed in with the camera they are there. Also not sure if anyone mentioned why the barrel and the slide are marked with one set of numbers and the other stuff is something else?

That is the receiver, not the barrel; the marks are workers marks.
The receiver is a DWM receiver.

The barrel and receiver were likely numbered at the time they were "mated", it is not factory work- but happened at the time of barrel replacement.