Thanks for the input. No worries, currently entries to the list are welcome as I am ignorant of most details, and am here to learn.
In the upper rear portion of the driver rear fender, I do see a covered hole that was possibly for the trailer wiring connector:
It does have a convoy lamp switch, but it is mounted horizontally under the instruments towards the passenger side. Looking at the holes, I suspect it may have been mounted where the headlight switch currently is.
Underneath, I didn't get a very good shot since there were ants present...
