Re: Restoration & Maintenance

Many, perhaps most, aircraft restorations are done this way. As long as the aircraft still has the original builder's tag on it, it is that aircraft.
Sound's like the Rio Grande had a similar philosophy. When an engine went in for overhaul, it was separated from tender, cab, domes, etc. Whatever pieces were ready to put back together, that is what the engine got. Case in point, 464 in Flint, has boiler barrels from 454 IIRC. Marty could fill in that detail. And of course tenders weren't sacred either.
Cars were even easier, as there was no builder's plate, after the CRS trusts had matured.
El Nehi