Thanks. You know, now that you mention it, when I saw the large wire output meter reading shaking like there was AC, I put the meter on an AC scale with the car running and I swear it was something like 22vac. I don't remember if this was before or after I disconnected it from the battery.
I also had turned on the headlights while they were shining on an object at night to see how bright the lights were. I then turned off the car and did not see any change in the brightness. I realize this is not a scientific check and reading voltages and current are for real, but just throwing out other things I can remember doing.
I may wind up popping the alternator back in the car to do just a few more checks. Like I say, electrical parts are not generally returnable so I'd like to be pretty sure (well, as sure as I can be), before I pop $200 for a replacement.