W126 dark tail lights

[old blue]

I recently replaced some burnt bulbs in my 85 500 SEL tail lights and noticed that the inner (vertical) lenses do not have bulbs associated with them. The holding plates are stamped with holes to receive bulbs, but there is no wiring.

It seems that I would want the entire lenses to be lit during the night for better safety.

Are they supposed to be lit?
What about 560's or euro's - are they the same too?
Can I get parts to plug in and go?
If not, could I order the existing outer tail light socket assembly and splice into the original to get the full lens operating.

Danke