So far as I know they are all wired just like the 70/ later isolated field setup. CHECK BOTH BRUSHES and make sure they are both infinity to ground (open to the case), and continuity between each other
I am pretty sure that the two wires are not the same as the old alternator . One is a field wire and one is a sensing circuit for ecm control. My megasquirt instruction call for 1969 mechanical voltage regulator