Rebuild 4 piston calipers or replace?

I have the Kelsey Hayes 4 piston calipers on my 72 340 duster, they are in rough shape. I was able to get them apart but two or three of the pistons are pitted and need to be replaced including all the seals etc.

Is it worth it to rebuild them or is there a caliper I can buy to just replace them?

thanks for any info