What about the 2 "X" between cartridge stamp and receiver?
Nice rifle! Any clean stainless KS is a real find these days and that one looks pretty good. In regards to the barrel stamp, I've seen some like that on the stainless rifles before, I think the guys in the Custom Shop liked putting some extra stamps on them
I remember one in the classifieds a few years ago that had a similar stamp, also a stainless KS.