I do not think these covers will close off the area intended. If you look at the cover you will see mounting holes that are shared with the rear spreader bar. Also note that one of the covers has a relief to clear the gas tank filler neck. With that in mind, look at the pictures of the body and you will see these covers will not come close to closing off the area intended.
Not trying to be critical. I have a 32 roadster and would like to do the same thing that daveyboy 1956 is trying to do. I saw these covers on Ebay also and thought this was the answer. After looking at them closely I don't think they will close off the area intended.