Most likely real IMHO.
-This serial font is seen on the refurb imports.
-The finish is largely intact around the new serial stamp.
-Serial numbers with no prefix are also not uncommon on replacement stocks.
-I also think this particular cyrillic prefix "НБ" would be easy enough to fake
If i had to guess, this is a very late replacement stock.
I've begun to wonder if examples like this -- Late production refurb, with partial stock serial, and no crossbolt at the wrist-- might be an indication that the late final "refurbishment" was part of an aesthetic, commercial make-over and not intended for re-issue.
Who knows.