Here's what my 65 GT roof looks like inside . There are 13 rubber grommets that hold a screw that goes through the roof and holds each clip. There is also a tinnerman nut on each end that holds another screw/bolt. My trim is still attached so I don't know how easy it is to release the trim from the clips. So, I agree with @toolmanmike, @mopowers and @Professor Fate it should be possible to rivet or screw the clips back on. The grommets and tinnermans would then just fall into the headliner. I'm thinking the rubber grommets are there just to keep the screws from poking through the headliner if someone pushes up on it.