IIRC, try to get a cap for radiator without overflow tank. It may be that the caps for overflow tank can be used on the earlier system but I can't recall and too tired to think it through at the moment.
My guess is the regulator was damaged. Whether its a points regulator or an electronic regulator doesn't matter in this respect. There's only so much current that can flow through them without damaging the internals. The points type is pretty straight forward - There's fusible links inside. Too much current and the link with blow.
