Yes it is still in place. The reason being the design of the orange material means it can only sag on one side because on one side there are rectangular perforation (for tiling purposes, I believe). Also I added almost an inch of material along the side of the headlining (outside the template, so loose folded material), so the excess material slid into the metal crevice (frame) running along the inside. I installed the headlining to try it on for size without the adhesive - it fit perfectly with no sagging at all!
I did not install sound deadening material before installing the headlining but I think it works fine without it.
Do not forget to put back the plastic screws/grommets.
Good luck!