Ok, its starting to make sense. I forgot this truck does have the passenger side intact. So it looks like the tan wire, aka low beam, will have one of the filaments of the outer bulb on. Then when high beams are clicked it would swap to the the other filament in the outside bulb along with the inner bulbs single filament.
This seems to be what OrrieG's reproduction setup does also. So I'll go with that. Thanks guys!
