[sameyrasmea72]

I am nearly positive that factory bucket trucks had no cardboard cover. The carpet was more or less a flat piece that attached to the back panel backwards at the bottom lip of the carpet with 12 screws and washers. Then the carpet just hung in place and sort of just covered the tank.

Most of the new carpet kits for the tanks are nothing like the original carpets, they are more preformed to cover the tank. I would think they were meant to be used without the cardboard cover as they seem to clip on the top of the gas tank.
When I put new carpet in my truck I just used a flat piece of carpet and used the original screws/washers and hung it just like the factory did. The sides are just sort of tucked in around the gas tank.