Thanks so much. That will be quite helpful. I can correct others the next time I play croquet, which is likely never. I'll be sure not to be so specific about implements going forward.
For other contributors, here's the latest: I pulled the alternator and it's an aftermarket part without any identifying label or number, and a different looking housing from the OEM Mitsubishi (A2TB2891ZC). Based on that, I won't pursue a rebuild.
I found a used and tested OEM Mitsubishi alternator nearby with a six month warranty, for cheap. Should it fail at some point in the future, it will be worth rebuilding. If the trouble arises again in short order, at least I'll not have invested much and will have a factory correct alternator.