Interior Lamp Position on 79-82 Sunroof Headliner

[Basin Motorsports]

I am putting a new headliner in my 1980 sunroof coupe, but don't have an old one to reference from. Does anyone know how far back from the front edge the map lamp sits? It appears in the center of the car (cross car), but maybe 3"-5" back from the edge (fore-aft).

[dagenham]

There should be holes in the cross brace(do sunroof cars have them?) where the original light is mounted.
I forget, does it have the backer board headliner or does that year have the old bow style headliner?