Both marks under the bolthandle seem to support Huvius' suspicion. The shape of the "crown/B" mark is not the one of the commercial proofmark. also, I would expect a crown/U on a bolt instead. This crown/B stamp looks very much like a pre-WW1 military inspector's personal mark. The other mark is the lower Half of an also pre-WW1 military accceptance eagle, upper half obliterated when the bolt handle was bent. and, this bolt body and striker nut are indeed several years earlier than the 1907-8 made rifle. These bolt bodies with the narrow gas escape slits and the detent for the pointed cocking piece were made for a small-ring "Transition" action, pre- 1902. IMHO the rifle had lost the original bolt and came back to the factory for a replacement. The Mauser custom/repair shop then fitted a leftover bolt from the earlier, military test series and numbered it to the rifle, as they ever did. The former head of the Mauser sporting arms department, Walter Roell, continued to do so until the early 1960s. He had the original Mauser numbering stamps and not only continued the Mauser serial number range up into the 128 000s, but also whenever he rebarreled or restocked an older Mauser rifle, he habitually renumbered the replaced parts to the gun's original serial number.
BTW, that "holy grail" of collectors, "matching serial numbers" is no guarantee that a German gun, especially a military one, does still consist of the parts it left the factory with the first time. By regulations peacetime military armorers got the needed spare parts unnumbered. They had the prescribed numbering stamps. After fitting a new part to an existing gun they had to number the new replacement to the gun. Only late in WW1 they were allowed to cannibalize other guns, resulting in "mismatched numbers".