A body console wiring

I'm a bit confused here but the 70 and earlier shifters had a switch connected to the shifter body with a 2 prong plug that I believe works the back-up lights. The 71 and later shifters do not have this switch attached. It was incorporated off the neutral safety switch.

From your description of the harness you have, it is an early style. How about the shifter ?

Hope this helps.