Sail Panel Boards

Stephen, you just don't know how much this has helped me. Now I know the boundary and shape of the boards and can make my own. Just one more question. Are the sail panel boards covered in the headliner material completely separate from the headliner itself and then installed separate from the headliner? Or is it all one piece and just glued over the top of the sail panel boards? Again, thank you so much. You have helped me probably more on this one thing than anyone else on the site.