I replaced the rear shift seal (or whatever you call it) when I did the short shift kit. I think I used needlenose plyers and a small bearing puller to get it out, and knocked in the new one gently with a socket. Mine was leaking a little.
Perfect time to rebuild your shift linkage. And, if your rebuilding your shift linkage, it's probably a good time to replace this seal.
I don't know what other seals you are referring to though.