What do these stamps mean?

[Olle]

Gotcha, thanks!

It came with a "42" 9mm barrel and one .30 barrel without chamber stamp. I found these three stamps on the right side of the barrel extension, plus a 4th one that you can just barely see. There's also an "N" on the lug under the chamber. Is this some kind of rework, where the old stamps have been wiped out?

The muzzle end has a pretty bad dent, so I'm planning to change to a 9mm barrel later on. I just want to be sure that I'm not dealing with something highly collectible here.