Definetly a restamped bolt. Here is a pic I found of a BYF42 that has not been restamped. The giveaway is the bolt handle surface has been ground down and the raised plateau is not there anymore, plus the fonts are wrong.

Since it is in a RC stock, i would guess that someone here did it to try to fool the unsuspecting. K98icon's are kind of getting to be a minefield if you do not know what to look for.

Looks like a nice gun and I hope it shoots well. Enjoy it.