Thanks to everyone for all the help and thank you Boris for all the great information and reading material!

I was initially disappointed that there were little markings on the gun. Nothing looks like it was ground off, but I was thinking it had been scrubbed somehow. I love these milsurps for their history and the arsenal markings are a neat feature to show people. But this is definitely cool in its own right. Can't wait to go shoot it!

I'll have to check the piston tube and shaft after work this afternoon for electro pencil marks.