Most with mismatched bolts could have been war reparations or field captures.. Russia was a big 're"-user of Mausers. They would refurb them, numbers didn't matter to them, function mattered. They would scrub them, pop the capture screws out, peen almost any and all German marks, and sometime blue the bolt as well.
For a shooter, numbers don't matter, it can still be a deadly accurate 8x57mm rifle, numbers matter in resale and to number counting collectors. As far as headspace on 8mm Mausers, the older Turkish and Spanish seemed to have the most problems.. The Turks used really hot ammo in older designs, that puts a whoopin on older designed bolt lugs, the Spaniards had what most deem questionable metallurgy.. I have not had an issue with either makers. The Turks also, were notorious for an everything matches, but the bolt, in my years I have seen 2 Turkish Mausers that "every" number matched. Yugoslavian Mausers and most Romanian contract rifles, they are like Chinese SKSs, there are tons of them on the market, even if it's matching they usually don't quite carry the premium that say a Cz, J. P. Sauer, or a W.z.29 branded Mauser does.
This is especially true with a Cz, lay a Vz.24 and a Romanian contract Vz.24 side by side, in the same exact condition. They are the same exact rifle by all accounts, but typically, the Czech used rifle will sell for more.