starter and plug wire boot question

Have a couple questions on this bike i'm working on. "83 GPz 750.
First, does anybody know the correct "RBK" type starter rebuild kit for the Mitsuba 8208 starter motor. I see these kits all over the 'net. Yellow cardboard, with vacuum shrunk plastic over the parts. I see some that cut off at '82 for the zx 750 so not sure.
Second, one of my plug boots has a bad resistor in it. Has anyone been able to successfully remove the internals?  I pulled on the screw looking portion this morning and it may be glued in there.

According to Partzilla, the starter for your bike fits on later year bikes, but not the 1982.

Good to know. I went ahead and ordered a 4 brush kit it looks like its correct from photos. Disassembled the starter today to have a look inside. Brushes were worn all the way to the woven copper connectors, commutator has a pretty deep wear pattern 1/8" or so where they made contact. Hopefully I can clean that up enough to work.