Is there anybody there????

I have a 1987 Dodge V8 5.3 Day Van with an Eagle Conversion.
All the trim covers up all the interior of the Van so I don't know whether there are captive nuts for seat belts in the roof frame for the 2nd and 3rd row of seats.
Does anyone know if there is before I start dismantling to find out!
There are captive nuts for the front seats, so I know at what level to look, but were rear ones a later addition for these Vans or were they installed from the earliest models?
Hope someone out there can help.
regards
STUART