The inner panel that houses the deck lid torsion bars had to be fixed because of water damage.
The body shop had no choice to tear this apart, blast and replace the damage.
My guess is that the trunk rotted from inside out.
Whatever it is, any way you look at it, its a drain for water to enter the trunk and needs to be welded shut. My car, albeit a convertible, has 2 spot welds in that vicinity.
I dunno. When I worked at CAMI we had complete white bodies on stands that were used in case a body got damaged on the welding line. Some of them sat for weeks before the need arose to use it. I recall a white body getting damaged during a "football" game (the line was down) when a big fella running for the ball (made of gloves) accidently ran into the side of it. It had to be scrapped.....