Beautiful interior Blindhuckster, hope I can get mine car close to that condition some day.
My car originally had the curved metal style package tray. The metal shelf drops down about six inches to a flat wooden shelf. There is a 10 inch tall metal panel below the rear window that attaches to a "L" shaped channel that forms the perimeter of the wooden package shelf, see attached photos. As I remember, the front of the wooden shelf was supported by wood framing from the floor, about where the step up is in the floor pan.
Also attached is another photo showing the straight style of package tray for the split front seat. There appears to be a curtain that covers items stored in this area.