The figures 145 and 146 in the pdf snippet of Clymer are not visible.
Maybe not, but the K1100 manual is here at Motobrick.com and it has a section all about fork maintenance—Chapter 31, p 31.11. Why don't you look into it? I don't know how K1200 forks are assembled. I don't use "hope" as a maintenance strategy; I use denial when necessary.
I have always removed the fork assemblies when doing maintenance including seals and bushings. After draining the oil, you'll need to remove that screw at the bottom of the slider to start disassembly. It can be troublesome. The best method is to give it a little heat, a little penetrant, then fit a long-shank hex wrench to it and jerk it loose. Don't be shy. To me, it seems easier to have the assembly in a vise for good leverage.
I'm sure seals have been replaced without removing fork assemblies from the yokes. Somebody is always doing stuff like that. You're certainly free to try it.
Live by the snippet; die by the snippet. Buying a
whole Clymer manual is a good investment; it's like buying decent tools. Using other manuals along with it can be helpful also.