Try cmsnl dot com. The Kawasaki GT750 wasn't sold in the USA, so it isn't going to be listed in most of the parts diagrams as most of the diagrams are only for the North American models.
However, cmsnl dot com has the diagrams for several Z750P GT750 models >> the earliest model I saw was the 1984 Z750P3. I don't know if the 84 P3 stuff would be the same as the 82. cmsnl appears to have the P3 fork spring guides & P3 fork seals. I would note the part numbers & any superseded part numbers for future reference. I saw one fork spring guide listed on EB.
1981 KZ650-CSR. Competition, Sports & Road.