I havent seen any chry co anywhere on the axle. I can try to get and get a PN but if you look back at one of dana67dart replies he posted a picture of a 67-68 backing plate and it matches basically perfectly
it should be something that's dead simple. it's BBP 7.25 (are you sure it's 5X4.5 pattern) so it should be a slam dunk. even if rock sent the wrong parts, or the wrong stuff is on there all the right junk exists out there.
it might be pain, but the path forward could be just rolling to the local parts store with parts in hand and playing the match game.
