What details do you keep for finding a matching replacement wheel later?

Seeing a couple of posts about people struggling to find one or two discontinued wheels got me thinking about what information is worth keeping from the original purchase.

My starting list would be the exact model and manufacturer part number, size, offset, bolt pattern, finish name or code, plus photos of the box label and any markings on the wheel. If a set is custom-made, I'd also want a copy of the final specification sheet or drawing.

For anyone who's had to track down a single matching replacement, which detail actually helped? Was the part number enough for a dealer to locate old stock, or did you end up looking for used wheels? I'm particularly curious about how people checked the finish matched when buying from a different seller.