10" Brakes from old or new b-body?

i've narrowed the brakes down to coming from either a 66-67 charger....
or a 71-76 charger,dart,or duster (all the same brake parts)...

the wheel cylinder 705a, is for early 70's to early 80's mopar...the shoes were ford.....FORD!! but look similar to the 67 stock charger shoes... but hard to determine since someone was stupid enough to put on ford shoes....

But being there are 2 different brake set-ups..i'm wonderin' if the backing plates are different from the mid 60's to early/mid 70's??? anyone know???