Your blower motor looks just like mine. Probably just differences in production years. Before you go to all the trouble of fitting new brushes, clean everything really well with some electronics cleaner. Then check the armature, where the brushes contact, for grooves and thickness. If it has major wear, it is not worth your trouble and you would be better off with Bob's (Techguy) suggestion. (After 2 motors and a second set of brushes on each in 2 years, I can tell you been there done that.)

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )