Ok, I did the deed. It was really pretty easy. The good news, the seals were easy to replace. The bad news, the key seal was pretty shredded and ALMOST unavailable anywhere. I managed to find and order one, paying way more than it should be worth, but to me it's more economical than buying a new valve. I'll be installing that when it comes in.
Disassembling:
Remover 8 cover screws and remover cover, handle, and key assembly as a unit. NOTE: pay attention to the orientation of the cover with respect to the outlet.
Drift the pin holding the handle to the key out using a punch and a hammer using light taps. This is almost able to be done with hand pressure alone.
Remove handle and spring from key.
Remove the seals and key spacer.
Install cover seal
Install key spacer first. Then lubricate key seal with silicone lubricant and install on key.
Install key into cover.
Handle installs reverse of disassembly and can only install one way.
Reinstall the assembly into the valve body, paying attention to the orientation of the cover to the outlet.