I don't know the part numbers without researching... but I can tell you that we get our Hydraulic Cylinder seal kits for our 580CK from "Equipment Part Source", Online LINK is:
The kits are good quality, USA made, and about 1/2 price as Case. The pictorials will clearly define which kits to order. Be aware that the 580CK used several different designs for the cylinder packing seals. I suspect the 530CK may be the same. You will need to look for an identifier groove style on the gland to order the correct kit.