Lighting Question or Woodie Owners

[JSabah]

I have a Lighting Question or Woodie Owners (or those knowledgeable).  My rear tail lights have 2 wires going to them and a socket that only has 1 pin (for a single element bulb).  This differs from the typ Ply wiring diagram.  I assume that one wire is the hot for the light and the other is a ground (as the rear lights attach to wood and therefor wont self ground).  My new wiring harness came with (also) 2 wires for the tail light BUT the socket rebuild portion has a double pin setup - It looks like Im missing a ground wire to the tail lights.  Did the original ('49 P18 Woodies) not have rear turn signals (or tail lights - which I cant imagine)?  I see that the only brake light is a single brake light in the center on the spare tire door (housed with the license plate wire- is that correct?

 

Have others simply added a ground wire to the new tail light housing so that there are 3 wires and gone ahead and used the double filament bulbs for the tail lights and turn signals and just kept the single brake light in the center or has someone cleverly added 2 wires and another socket to the tail lights for a brake light? Dont think it matters but Im now 12V ....