I hate Spanish Mausers, but the bolt and action serial numbers not matching does not matter.
Tell that to the pile of bolts, bolt parts, trigger parts, and actions in my stash (mostly barreled).
Headspace is all over the place, and fitment is extremely varied.
Even if I can find a bolt that passes a "Field" gauge test (let alone a "No-Go"...), it is close to impossible to find a safety, sear, striker, bolt shroud, and cocking piece that will get along with that bolt as intended.
They may have been production rifles built, ostensibly, as having "interchangeable" parts. ...But the reality is that they're all hand-fitted basket cases - especially the 1893s that were scrubbed and converted to 1916s.
The headspace issues can be avoided, to some extent, with a custom rifle that has a new barrel. But the sear, striker, cocking piece, bolt shroud, and safety issues still remain...