Tail light lens

Yeah, the '65 diagram shows it getting power from the same connection on the wiper switch. The wiring diagram lists it as a B1 wire connecting to one of the two B terminals on the switch. In the diagram, that circuit is off by itself and not run along with all the other main dash harness wires, but, this is just a diagram and sometimes they do that for space or to just make it easier to display. It may still be a main harness wire.