KH brakes questions

You can send them through RockAuto and have them Re-Manufactured
1971 PLYMOUTH DUSTER 5.6L 340cid V8 Caliper | RockAuto
You'll be lucky to find them else wise . Or have someone locally rebuild them if you know of someone local. Some here have ordered one and got the wrong side shipped.
[FOR FREE] - trade driverside kh caliper