Mine acted flaky for a couple of years before I finally got it figured out. Since then, it consistently charges at about 14V with a stock alternator.

So I clenaed it up and since for me to get anywhere I had to use this car, I put it back on and Alas! It Worked! It must have indeed been the gunk all over it. Below is a comparison picture. Ive ordered a new one for $15 (not a Bosch though, do you think it makes much of a difference?) and will have it on hand for when I have the warm space and time to do a thorough alternator cleaning.

Thanks everyone for your input. These forums are great!
Have a good day.

Good news! I'd suggest not going with the non Bosch regulator. There are 3 parts in the Bosch alternator, the green resistor, the regulator (behind the plastic cap insulator) and the brushes (the only part that wears). That means if the non wear parts only go bad if shorted out. Since yours is chaging fine and the brushes look a bit short, I'd spend the money on a new set of brushes instead (if you know how to solder). I have seen a non Bosch regulator, it would not even fit physically (it was too big) and cheaply made. How long are the brushes? Maybe it has a bit of life left?