Solid state regulator conversion confusion!

In this case I can tell just by looking. The terminal to which the green is connected HAS NO INSULATOR.

This stuff is dead nuts simple, but complicated by problems such as this, here is the deal:

69/ earlier alternator have one brush grounded. The old style regulator has ground, switched 12V to it, and the green wire to the only field.

70/ later are SUPPOSED to be fully insulated from ground, with two brush/ field terminals. The VR gets ground, 12V and the green wire to either field. The remaining alternator field is also connnected to switched 12V

There is a number of reasons why late model alternators INCORRECTLY get one brush grounded. This includes...........

Sloppy rebuilders who leave out insulator hardware
Sloppy rebuilders who "convert" early (grounded) ones to isolated ones, then incorrectly do the conversion and leave it grounded anyway..........

and so on............