A lot more wears out on a starter motor than the brushes. I used the kit in the link below to do a complete starter rebuild. It is a very complete kit.
I removed my original Delco-Remy solenoid end cover and put it on the aftermarket solenoid. See third pic. It fit perfect and doesn't have the extra unused post.
The seller has kits for any starter even tractors.
https://www.ebay.com/itm/13266899887...MAAOSw4WRbJ~ZV