My K20 had similar damage to both sides. I was able to get a couple of good used from diligent online searching. K10 and K20 are the same. C20 & C30 with rear leaf springs are also the same. I may have one or two used that are leftover that are much better then yours but they won't be perfect. I will look for them if you want. I may have tossed them on the last metal scrap cleanup. Also the cast shackles come up on e-bay new old stock as well I probably have one or two but would like to keep them for spares. I can send photos that show the part numbers. All of this shackle stuff has to be in good shape with good fitting parts or the truck will handle poorly. If you use good parts with no slop and keep it greased up they will last forever. And yes, do not overload the truck... I guess I can't post any photos here except by link. I'm linkless, sorry... If you need more info just ask...
