Sorry to be a party-pooper, but the finish on the scope mount looks rather too good to be true. Bluing is a form of controlled rusting, and this tends to age even if the piece is never used. This looks to me like very "young" bluing. I may be wrong, but in such cases a hands-on examination is vital - and unfortunately impossible with online auctions.
Please note that the seller does not produce a single item of evidence that the rifle was made up as a sniper by the Russianmilitary, rather than by John Q. Bubba or anybody else at any time up to and including just before the photos were taken.
And one is impressed by the chuzpe of the seller in writing "Barrel bands, bolt and floor plate do not match, which is correct for these rifles..." - as if an all-matching rifle were therefore "incorrect". That is turning the notion of "correctness" - which is arguable anyway - on its head! He should have written "... which is common for these rifles".