Why stamp at the crossbolt then? The fact that the stamps appear specifically at the crossbolt is significant. Couple that with the fact that crossbolt placement is crucial for stock fit-- i.e. a crossbolt that has shifted position over time due to warp could very easily render a stock useless.
Once in place, a barreled action mitigates warp and prevents shifting of the crossbolt.
I have also become increasingly wary of the terms "non refurb," "original conditio,n" and "as issued" -- to the point that I use them in italics or place them in quotes as a reminder that these terms are far from definitive, and really only gauges (reached via consensus) of the overall condition of any given piece.
Now.. granted it's apples to oranges..but it shares some commonalities... I own many rifles that are close to twice the age of an SKS, Mosins particularly come to mind. Know how many have been affected by a crossbolt moving over time.. none. If crossbolt moving were an issue, then why didn't the Finnish who ripped apart and salvaged Russian weaponry to manufacture their own and who make the vaulted and accurate M39 make a huge deal out of it. If a rifle is going to loosen and hammer on a crossbolt, the x54r round would do it, maybe the wood, nope, the Russian Mosin uses an arctic birch like an SKS, same shellac finish as well.
Why didn't other nations worry about the crossbolt mysteriously moving? Did no other nation care enough to make a deal out of it.... Romania, nope, Yugoslavia, nope, China, nope, Albania nope...the Trinity makers, nope, nope, nope. If one was going to, why didn't China, given how close they "supposedly" followed the Russians?
Wouldn't Russian Mosin crossbolts been subjective to the same Russian inspections while in the same Russian storage? Compare a kind of spindly long Mosin stock to a shorter thicker SKS stock, which would be more prone to twist and warpage?
Is or was there some kind of failure rate with Russian SKS stocks/crossbolts exclusively that possibly don't affect the other ump-teen thousands made by other nations that warrants crossbolt examinations. Or, while there is maybe known failures, the rest of the makers don't deem it a signifiant enough failure rate to worry with? Is this why so many Russians are found frequently restocked?
If crossbolt inspections were so important, how come laminates with 2 crossbolts don't have stamps around the rear crossbolt? My understanding is it strengthens the stock to prevent splitting at the wrist, so if it were loose, in theory you could split a stock and in turn loose a weapon on the field of battle.