That'll work. I fixed many of them that way (and the vacuum advance still works). The ball bearings fix the two plates together and prevent wobbling

When the stock plastic bearing reatainer breaks, the ball bearings fall out and the plate assembly wobbles. Since the stator signal ring it bolted to the top plate, it allows the signal ring to wobble causing high RPM issues

Cut a disc out of polypropelene, drill a 1" hole in center, and three small holes for the ball bearings. Reassemble. More information