I have to answer both ways, I guess, or maybe "decorate at will" with reservations on collectibles. But a custom decor job gains collector acceptance the longer ago it was done!
Restoration is another matter too. With cars, restoration (even to a condition better than original) is accepted and even expected. But collectible guns lose value and "legitimacy" if restored. The patterns of wear and abuse are considered part of the story/history of the item and shouldn't be destroyed by refinishing.
I am NOT a camera collector (I have to keep reminding myself of that), so I don't know what effect restoration has on collector camera value.
I would personally hesitate to have a chrome camera painted, as it would be hard to return it to new condition, and the serial number could "tattle" that this was not a black-paint body originally. But I think Brian's badly dented Nikon rf body is an example where the refinish added more value than it removed (if any).
I'd have less hesitation about repainting a painted camera. I would never gold-plate a camera or polish up the brass to look like gold. I think I might like an offbeat color like grey, blue, etc. This could be a conversation starter, to put my photo "victims" at ease quickly. 🙂