4 piston calipers question

'65-67 Mustangs use the same pistons and rebuild kits, sort of. There are early and late Mopar dust boots. Mustangs only used the early boots. There was a time when rebuild kits had four of each. Some kits these days only have the early boots (or at least last time I looked).

I bead blast calipers after they are cleaned of any fluids.