The headliner is a plywood board, covered w/ padded fabric.
The plywood has concealed perimeter stainless oval head Phillips screws.
Feel through the padding to locate the screw head, untuck the fabric to expose the screw for removal. The padded fabric is glued to the plywood, except for an unglued arc at the screw.
In my case there were instances of several screws about an inch apart, while most were 6" to 12" apart.
