I don't think your denso is internally regulated....I have one off a 2000 ram van. it uses external reg, wires exactly like the 60's dual field. Don't forget to add a larger (I used a 4G) wire between positive stud on alt and positive on starter relay.

Is it possible you are confusing volt reg built into pcm vs standalone VR...and calling it internally regulated? I looked at lots of alts in wrecking yards and all the mopar ones of the vintage you speak had two studs for external ...trucks, minivans etc...