1973 Duster charging issue

Hey guys. My 73 has a issue with the charging system.

My battery was dead at work yesterday, so i called AAA and they came to test and replace it.

I needed a new bat anyway, but he said it was not getting charged. I didnt see the results though.

I checked it this morning, car running, bat voltage is 12.25 volts, so i guess it is the alt, or could it be the voltage regulator? How do you test the VR?

the VR is new though, and i replaced the engine harness with a new Evens harness just last week.