The rubber cap like bottom can be replaced with easy to cut in shape cork sheet will do. Just rip off the thin strip where the serial number for the ID and other info that might be needed later. Have it glued or put on a clear tape and put it on the side of the white plastic sidewall will do.
It is almost impossible to keep the bottom rubber covering intact in one piece. The rubber is covering the whole base section and it won’t be a problem without it I guess. This is not an epoxy because it is still gummy and sticky. This is like the adhesive used on the double side tapes. Goo Gone worked well to remove those residues.