Startr comes out real easy one these old trucks. There's basically 2 bolts that hold them on, one on top that you can see, then another directly opposite of it on the bottom. Some years use a stud and nut instead of a bolt, mine was that way, which also serves as a mounting poin for the chassis ground strap.
As far as overhauling, look for a shop that overhauls alternators and/or does electrical work on cars. They'll have the equipment to properly test the armature ans windings, plus turn the armature if necessary.
