It's really brittle, not surprising for age. Seems like front and rear are held in only by windshield and back window rubber seals. Can't get metal "sail panels" out either, hanging up in rear window latches. Might break out the body manual, now there's an idea lol! Hope the headliner is avail aftermarket, it's a little rough.
Once all the trim screws are removed, coat hangers, dome light and any seat belt attachments. Work a putty knife around the edges to break the glue and it should all fall down. Mine did. It was glued up there too