Deck Filler Plenum?

[MoparSam]

I was inside the trunk of my '68 last night poking at rust and knocking out epoxy and filler (so I could get an idea on a sheet metal order for AMD) and I noticed the deck filler plenum is only attached at the base of the back glass channel and at the top of the trunk gutter, but not on the sides to the bottom of the deck filler panel.  Any one got an idea on why it is done this way and what in the wide world of sports is the plenum for?  Support? Thanks in advance!

[Charger-Bodie]

Its not welded to the deck filler , but it is (supposed to be) glued with a foam type caulk.

[1charger69]

is this the pc that the speakers set into?? behind the rear seat??

[MoparSam]

Its not welded to the deck filler , but it is (supposed to be) glued with a foam type caulk.

Ah, that makes sense with warping from welding, but they kinda went thin with the caulk cause there is only a 1/16" wide or less bead.

is this the pc that the speakers set into?? behind the rear seat??

Almost but not quite, it attaches to the package tray and to the top trunk gutter, directly under the deck filler panel.  Any body know what the plenum is for?  Can it be taken out permanent?

[b5blue]

I think it is a stiffener and mount for rear defroster.......? Photos? 

[MoparSam]

I don't have that good of lighting in the barn I work out of and the Chargers not moving right now but METROID has a good picture of one that shows its location.