I don't know the details of either the S&S or Harley alternator.
But, there are two functions here. An alternator produces AC,and a battery is DC so all of them, whoever made them, have a diode pack with at least two diodes, and most have more. This turns the AC output into DC.
Next there is a regulator that samples the output and from it, derives the excitation power that feeds the field coils to make sure the output voltage stays at the 14 and a bit volts for battery charge.
In a car alternator, the two functions are utterly separate and crucially, none of the output power passes through the regulator. Most of them these days do it all in the alternator case, but separate regulators were in some car types.
There are various ways of doing things and
this explanation is ok, although don't take the numbers of diodes for granted as I can show you an alternator with only two diodes and no 'diode trio' (my 2CV alternator in the vintage trike).
On another related topic, the rubber mounts for the regulator look like what I call A35 exhaust mounts. That being so, they are interchangable with a more flexible type, the so called Mini ones. See
here for ideas. Any decent exhaust fit place should have loads of them and as you can see, playing around won't break the bank.
