I had my headliner in my 46 done. The apolsterer cut new cardboard from the old panels and covered it with a foam headliner material with a finish on the outside. Look here
http://pg.photos.yahoo.com/ph/sublime589/album?.dir=4e07&.src=ph&store=&prodid=&.done=http%3a//pg.photos.yahoo.com/ph/sublime589/my_photos