Sail Panel Dome Light Wire Routing ('65 Barracuda)?

How does the passenger side dome light get routed over from the driver's side? Does it just tuck under the headliner somehow? I notice there is a "nub" that should snap into a hole somewhere (see photos #2 and #3 for nun location). Thank you.

Passenger Sail Panel light 1.JPG

Passenger Sail Panel light 2.JPG

Passenger Sail Panel light 3.JPG

Passenger Sail Panel light 4.JPG