The miscellaneous markings on mosins are usually location of manufacture of the individual part, proof markings, inspection markings and acceptance markings for various reasons.
If the bolt is shiny silver chrome its been rearsenaled. Yours has been rearsenaled and force matched as cai only imports those types. Force matching is fitting the parts then stamping the serials.
This isn't an issue with most mosins and only a factor with types like finnish which can affect value.
But overall the soviets aren't big on record keeping and the markings are for internal factory and armory use and even then merely as a means of sorting good inspected parts from unknown parts that haven't been fitted.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...