I'm replacing my filler panel behind rear window. After cutting out old panel I noticed a deteriorated insulation type material between the top piece of sheetmetal and the support metal under it.
My question is this (do I have to replace this insulation type of material before I weld in new panel?) :confused: Is this a anti sqeek device from factory?

Also can I use standard seam sealer in the seems where the lead was an the sides of panel? :confused: