Don't recall seeing a factory drawing or diagram showing a 69 nonm-fold down rear seat and package tray arrangement
As a start you might want to look at some of these threads and the trunk pictures in the unrestored picture section
- 69 April San Jose M Code Mach I - Unrestored Picture Thread
- 69 NJ 428CJ Mach I Unrestored - Picture Thread
- 70 GT500 - Unrestored Picture Thread
All will show some of the basic brackets, hardware, panels and other details to start
Here is another thread with pictures of panels and hardware from the front/forward side. It focused on the rear seat upper trim for a non-fold down
http://www.concoursmustang.com/forum/index.php?topic=19189.msg121080#msg121080Discussion of the package tray and insulation panel/layer
http://www.concoursmustang.com/forum/index.php?topic=4806.msg26752#msg26752Additional pictures That have been posted in other threads
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So what details are you missing at this point?