"Slight" overcharging

To check the VR circuit voltage drop, rig your multimeter to as close as you can get, electrically to the ignition terminal of the VR. Do not disconnect any wiring, it must be all "nromal." Connect the remaining probe, that is, "stab" it directly into the top of the positive battery post.

Turn the key to "run" and take a reading, which should be very low, down in the tenths of one volt. You would like to see "the lower the better." Anything more than .3 AKA 3/10 of 1 volt, investigate. Any drop there will be ADDED to the charging voltage.

My 67 Dart had about 1 1/2V drop. assuming the VR was 14, that means the battery saw 15 1/2 when running.

GROUND

The ground can also do this. Get it warm figure out how to get it up on fast idle to simulate low/ medium cruise RPM and take this reading first with accessories off, and again with everything on, lights, heater, etc

With it running as above, stab one probe HARD into the metal mounting flange of the VR. Stab the other probe into the top of the battery NEG post. Again, you would like very low voltage, zero is perfect

It is always possible that a VR is off a little bit. Someone is selling adjustable ones. I've heard a few good comments, but I really know nothing about them. However, normally you should not need an adustable VR