The issue is in having uncommon configurations, such as the sniper, or a soviet stamped single-action nagant pistol. Fake country marks is another thing...taking a rifle that's common from one fab and passing it off as another can be rather profitable for the trouble involved.
The bulk of them are $100 cheapies, but fake a 95% or better uncommon model, and you have a hefty chunk of change for cheap.
Sure it's not Mauser price hikes, but on a gun this cheap, nobody expects that. I have seen a few models stamped to be older than they were (pre-WWI stamps on a WW2 era rifle), and seen a nagant revolver that wasn't russian made at all (a Chinese interpretation of the design) stamped with soviet marks. The first giveaway was it had a factory style cylinder in the correct bore that didn't have a gas seal, there was a number of other things, down to stamps in the wrong places, wrong stamps used, etc. How I knew is I owned a real nagant of the exact year they said theirs was...same fab theirs claimed to be too, it was almost like comparing a colt 1911 to a Rock Island.
I'm suspecting it's some newbies trying to see what they can get away with before they do it to something pricey.