Voltage Regulator
I believe that is nothing more or less than blue lipstick on a "nice pig." In other words the heavy duty regulator (I think it's discontinued) which was sold by both NAPA/ Echlin and Standard Blue Streak.
"Slant Six Dan" went on some rampage about it some time ago. Evidently his complaint is that the blue paint prevents it from grounding.
So in other words, make certain you grind off the paint around the mounting bolts
Frankly, the 70/ later factory electronic regulator has always worked fine. You do need an isolated field alternator, IE 1970 or later, with two field connectors
The Standard version (Blue Streak) was VR128, NAPA/ Echlin was VR1001
The NAPA one is/ was sold under several part numbers with different vehicle pigtails/ connectors