This is a nearly six year old thread.....
The problem was solved and the hole repaired six years ago.
The panel adhesive worked just fine and is holding up perfectly.
And no, that panel does not un-bolt from the tank. It is a part of the tank assembly, it is the panel where the tank assembly date is stamped.
Those bolts you see along the seam allow you to remove the assembly, meaning the tank, firewall portion, top of the cowl and interior dash area as one unit.
The description is from Les Andrews Vol. I, page 1-179