My 68 XR7 has the parchment as well. When I bought the vehicle a couple years back the tray was re-done with a sheet of plexiglass and some horrible 70's cloth glued to it. I had looked for a tray to use as a replacement, then recalled what a buddy of mine had in his Fairlane. I went out and bought a sheet of 1/4 inch plywood and created a nice unit using the old plexiglass as a template (it did fit nice, just ugly). A little 1/2 inch foam and some black vinyl rounded out the tray nicely. Since I am not into the car for originallity or big $$, the whole deal was probably around $20 and look pretty good!
I've seen different colors, mine is red. Usually, if you have the decor package, they package tray is the same color as the dash, usually black or maroon.
You can make one out of fiber board, the brown 1/4" stuff sold at hardware stores, similar to the peg board material. Cut the shape out and put a varnish on it beofre you paint it. The varnish (spray or brush) will prevent the final color from soaking in and looking botchy.
I think you can get new package trays from John at "JOHN'S CLASSIC COUGARS" but if you want a different fix:
years ago when stuff was not available, I used to get either fiberboard at a hardware store or quarter inch plywood and spray paint it flat black, then take the spray 3m adhesive and spray it all over the black side, next take a sheet of vinyl window screen and lay it over the still tacky spray adhesive and let it dry over night. The next day I would spray it again with a semi-gloss black paint, let dry and install. Nearly looked original and lasted forever..