Disc Brake ID help

I have a 1970 Plymouth Duster with later modle disc brakes but I can not ID the calibers.... any help? Numbers on the raised pad in the first pic are 5031A and they are stamped.
Number in the second pic are.... top line 777 second line next to mothers stamp is 95020A third line 137 the rotors are big bolt pattern

Thank you....HemiMark......Anyone headed to the nats???