I can't tell what is like in the States but here in Italy for instance is forbidden to change ay serial number, but I'm almost sure that a SILESIA mark if erased would not mean anything.

It's OK to remove it. I have seen many people erasing that on their CAI imports. But those are cheap guns. On expensive items, if you care, then, (1) don't let it come; (2) if it comes for some reason, keep it there.

Many ads for the sale of lugers begin as "NO IMPORT MARKS",,,,
if removal is done, then this will become yet another deception in the world of buy, sell, trade......

We already have enough of the "build your own all-matching" lugers with the ads for WTB a "matching" replacement part...I sincerely doubt a seller of one of these weapons will ever disclose that he put it together himself.....

Great Point!!!

In semi-auto domain, the situation is not horribly bad. At least, there are many original finish original matching parts items available. I did a little bit research in MG domain, most Form 4 MGs in dealers sites, from Schnellfeuer to MP40, are parts gun.

Guess you could always use the ol Forced Matched ploy, and never say who actually forced matched it. If you did it now or it was done in Germany 80 years ago, is there really a difference?

On all types of guns that I have seen, modification of number on non-regulated parts (such as barrel, on some small parts, on accessories, etc) happen from time to time. But modification of number on regulated parts, such as long gun receiver & pistol frame is extremely rare.

But those are legal guns. On illegal guns, God knows.