CE (Commutator End) bushing Delco #1839345, is still available from DEERE as part # R40801, @ about $3.
Brushes, Delco # 1881838, DEERE # 1881838, are still available from DEERE as well @ about $3.50 each.
DE (Drive End) bushing, Delco # 1883730, seems to be NLA. I"ll try to post back with a generic part # for that one. (3/4" ID X 13/16" OD X 3/4" wide.)