v8 pedal conversion from Slant

on my 66 slant dart, I removed the old rod type pedal and put in a cable v8 type. Now the pedal I bought was this new one from eBay, however it does not have the little white plastic bit that is at the top of the back of the pedal. I suppose this is to keep the rubber from wearing away as it hits the flapper. Can anyone give me an idea of what that white plastic bit is made out of? how thick? And what I can use to mimic it? And type of glue that will hold from rubber to it? Thanks guys