Un-converting a Powermaster swap

I realize this doesn’t solve your issue, but Powermaster makes both 1 wire and factory style Mopar alternators that use an external voltage regulator. It’s a brand, not a style of alternator

I assume you’re talking about a 1 wire alternator, and switching back to one with an external voltage regulator.

Do you have an aftermarket wire harness in the car? Because a lot of them are set up for 1-wire alternators. If you have an aftermarket harness adding an externally regulated alternator might be a very different operation than adding one back into a stock harness that has a one-wire alternator installed into it.
PO rewired the engine bay and installed the awful 1-wire setup (Powermaster 75191), I'm not sure if it's an aftermarket harness or he did it himself. (I think the latter, going by the receipts I have.) The stock wiring looks fairly simple to redo, if necessary-assuming I cannot find a stock harness.