My bike came to me without one and the footpeg bracket was broken on that side.
I cobbled up a shim from a thin walled tube from an old direct vent heater pipe but
there was a gap and I was worried it would backfire more than normal so I bit the
bullet and got a new one. They are very soft and malleable, if you don't damage it
getting it off then back on, go ahead and reuse it but if it mushes up you will have
to wait for a new one...