Rear Quarter Panel Repair Ideas Options

[TargaToy]

So once again I find myself going where the sun don't shine.

Eventually, I plan to post the receipt from where the body shop charged the interim owner for "replacing quarter panel"...but that's fun for another day.

Here's my question: Am I correct that, from the factory, the little void in the point at the rear of the quarter panel (above the tail light) is left empty--or full of spray foam--and that there's a very large glob of seam sealer supposedly preventing tire-slung moisture from finding the foam?

I had to open mine up all the way and I'm toying with actually welding in a custom baffle in front of that pointed tip so that I could seal it up tight from the front side of the baffle. I would do this as part of the process when I fit in the new fender section.

What I want to do is make sure moisture can't get into that rear point and fester.

Anybody who's reworked the rearmost part of the fender/light socket, what have you done???