68 or 72 Alternator

Actually 2 wire and 1 wire is not exactly correct description LOL but I know what you mean

You can use the later 2 wire field (isolated field) by simply making a jumper wire for one field connection and wiring the rest up as the 68.. Does not matter electrically which one

If the harness you have? has the newer triangular shaped harness plug I would obtain the 70/ later regulator and hook it up as per later, that is 2 field wires

Maybe I misread, I would be careful mixing 70 and 72 harnesses.