Alternator polarity?

That would f-d up if they supplied a squareback with one field grounded.

Most a-bodies (ignoring Leece Neville and other rare options)
Through 1969 Model year. "Round Back" with one insulated terminal and one brush uninsulated and grounded to case.
1970-1971. "Round Back" with both field terminals insulated. Uses Regulator with triangular connector plug.
1972-76 "Square Back" with both field terminals insulated. Uses Regulator with triangular connector plug.

Dana - your illustrations got out of sequence.