Duster Brake Combinbation/ Prop Valve

My first job on my newly installed hoist was removing this valve. Was still a pain in the *** because of headers but a lot easier than lying on floor. Anyway after stripping the combo valve this is the damage i discovered on one of the pistons/valve?. It is butchered and obviously it has been jamming in the bore. Can you buy the replacement parts for these or is it a new Combo Valve. I had bought a seal kit from Muscle Car Research but didn't expect to find this.

Hoist.JPG

Piston combination valve.JPG