I'm not sure.
The light may be what the extra plug is for.
I cut mine off on the recent replacement in a 73.
I can hear that stud "grinding" on the horn contact plate when I turn the wheel.
I understand you are not able to find one with a roller stud either then.
But IIRC the older ones he sells are better with a roller.
I did look to see if I could transfer the pick up between old and replacement assemblies but it did not seem feasible.
