Thanks beermanpete and bludestiny for the help!
Ahh yes, I had to cut back the harness more and it seems the "L" (lamp) on the alternator has a spliced wire that may be going to a switched 12v source. The "S" (sense) is connected to the BAT on the alternator.
The car runs fine. Runs even better after the dizzy and msd upgrade. All electronics and gauges work. The volt gauge seems fine. Only weird thing is when I turn on my car lights, I see the gauge move a little towards the right. I would think it would move towards the left since it is drawing more energy?
Anyways, from what I can tell now, the external regulator is sitting there connected and getting power, but it is not wired to the alternator. So I'll go ahead and disconnect that when I get back home and see what happens.