GG has 179 pages available to the public, currently. The first 77 pages look like what we have already had here at the Forum - crew debriefings, passenger 302s, etc.
The bulk of GG's file is flight management stuff, which in includes the flight path, weather, and similar issues.
It also has a three-page report on Earl Cossey performed by SAs Mathis and Henry, with good ol' John Detlor weighing in at the end.
There is a juicy tidbit on Cossey and Hayden on page #229 (127 of PDF file):
"In May, 1971. NORM HAYDEN, Renton, Washington, purchased a new airplane and needed two parachutes. COSSEY packed two parachutes which were furnished to HAYDEN on or about May 21, 1971. He (Cossey) described these parachutes as back parachutes, commonly referred to as "emergency" parachutes."
This suggests that Hayden bought his two parachutes from Cossey. So, perhaps they were the NB-6 and Pioneer as Coss had stated. However, Hayden told me that he didn't remember where he had bought them. Also, RMB has written that Hayden told him that he bought the two chutes at a military surplus store, I believe.
Remember, both Coss and Norm told me that they had never met the other. This story continues to get stranger.