Brushes are shorted to ground.

I assume if my brushes show continuity to the alternator case and body ground that my alternator would not charge properly? I was driving it on Friday and the voltage regulator connector slipped off and it was charging 16.5 to 17 volts for a few mi tues. I fixed that and ensured the connector would not fall off again, then it was charging at 14 volts as it should. I took it out today and it started charging as usual then after a while it was showing 11.5 v with the A.C. on and about 12 v with the A.C. off. It' a 74 Duster with the stock square back alternator and an adjustable voltage regulator.
Am I on the right track with my thinking?
Cley