Tim, if you want to save some money on this you can find a cheaper rear window but still buy the other items. The window will sell for about $200 on it's own, the tray would sell for about $350 on its own, never seen pricing on all the parts, that is how I got to $450. If you want to get another rear window and leave this one with me then $300 for the rear tray and hardware would work. Just trying to help out.
Okay, great. The package would include the rear window in frame (date code is AS2 GY or April, 1972, not that it matters to you so much with your 76, storage tray with latch, hinges for attaching the tray to car, top lever latches for top of window frame, lower receiver brackets for holding the lower pins of the window. I would recommend you buy a new rear window gasket as this one is pretty brittle and a softer new one will be much easier to install and easier on the glass. I have the window out now, the gasket out now, and I can have the brackets and tray out tomorrow. Daughter's birthday party today. Total for all of it would be $450. Let me know if you are still interested.