If you want to duplicate the 1958 version of the Hog, do as Ken said and carve one from wood.

With the Sig kit, just strip the covering away where the backrest will mount and epoxy it directly to the wood. Make sure it fits well to the turtledeck and get good squeeze out. Wipe off the excess with a bit of alcohol on an old cloth before the epoxy starts setting up, and use a piece of tape to hold it in place while the epoxy cures.

Hogflyer