Yes, you can rebuild it but first check a couple things that may be a deal breaker. First, pull out the shaft and see if it is scored where it runs through the brass bushings in the housing. Usually the scoring happens around the top bushing area. Next check the advance weight pivot pins since often these are worn halfway through. Check out the points cam lobes for wear and roughness as this will eat a point rubbing block up which will change your points setting way to quickly. Give it a general look over for wire fraying, plate warpage, screw threads in the plate, and anything else subject to movement or wear. Any bearing supply place will have oilite bronze bushings although you may have to get some close and turn or hone to exact size. If the shaft and/or pivot pins are bad it's probably best to buy new.

Evan