Yup, 5/8" thick plywood with carpet over the top of it on the passenger compartment side. It has a metal strip around the edges held on by flat head phillips screws. They made at least 3 versions from '64-6 and I don't think the changes were made exactly on the model year change. The '64 version was larger. It covered the inner wheel house too. It also had rubber feet that rested on the trunk floor when the panel was lowered. Most '65's were similar but without the wheel house extension, and some had the feet, and some didn't. Also, '65-6 models with the 14 X 5 1/2" wheels had a slot cutout in the panel for the wider wheels. By '66 they didn't use the rubber feet.