I restored one recently, so I am familiar with the parts/operation.
The panel is only installed/supported by two aspects.
The panel is a tin piece which is painted grey like the rest, and is rectangular, with two large rectangular holes if you will. You can see it in the first pic, the holes allow you to see the outer sunroof panel beyond with the black X, which is actually contact cement with a bit of the old insulation which used to be there. You can actually see some of the old tan material, like the one in your first pic where it is being touched.
First is that it actually rides/slides in the channel on the rails mounted on either side (Left/Right) of the roof opening.
Second is that it is not like some modern sunroofs, where the finish panel can be moved up and back independent of the outer sliding sunroof section, but rather it moved up and back at the exact same time as the outer section. This occurs, because the inner finish panel is attached to the out sliding roof section by plastic pins that go through rectangular holes on both panels. Those fasteners go in the rectangular holes you see in the third pic
My forth pic show you they type of fasteners that are used. You can actually see the remnants of one in the hole second from the right.
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