If you have a rifle re-chambered, say from 458 to 450#2, would you also have it re-proofed?

Would you buy a rifle that had been re-chambered that has not been re-proofed?

Would you buy a rifle that has been made by a gunsmith on a shotgun action that has not been proofed?

Would you pay the same for an un-proofed re-barrel or re-chamber as you would for gun built as is.

Just curious.