Just now getting to the interior on my 69. I purchased the interior kit a few years ago. It appears that I have to reuse the metal piece at the top of the side panel which also holds the interior window felt. After removing the felt and the material, the bottom of the panel is simply cardboard which is attached to the metal. It appears that the cardboard was attached to the metal by piercing holes in the metal and then it was folded back over the cardboard. My question is, how should the new cardboard be attached to the metal so it will sta