A problem with removing the Giha vinal roofs is that the rear quarter windows are smaller than the regular Coupe windows. After you get the vinal off, your going to find some rather ugly filler pieces that make up the gap between the size of the regualr windows and the Giha windows.

The holes are the same between the standard coupe and the Ghia so you could replace them with the standard windows and seals. Then you would also end up wanting to have all the holes filled where the chrome strips go.

Then as NTFDAY mentioned there is usually some pretty nasty rust under the vinyl.

If your going to paint the car anyway, I would go ahead and pull up the vinyl then see if you want to go thru all the work or just put the vinyl back on.