No, I don't do Facebook apart from looking at Marketplace. It is Facebook that destroyed this forum. Someone in this forum started a Facebook group with the same name and most of the users left and went to Facebook. I prefer this type of forum.
Do you still have the reverse lamp harness?
I just realized that the factory T10 and Muncie didn't have a reverse lamp switch. The cars it was used in had a rod that connected to the steering column and the switch was on the steering column. The rod was used to force the transmission to be in Reverse in order to move the key to the Lock position. A collar on the steering column rotated, like putting a automatic column shifter in Park.
Since you have an aftermarket T10, does it come with a reverse lamp switch? If not, Corvettes with Muncies (probably pre 1969, when the key was still on the dash) had a switch that mounted to the outside of the transmission and was activated by the reverse shift lever. You may be able to make the same type of switch work on the T10 if you want to have operating reverse lamps.