Personally I ran my 500/4 for nearly a decade, for much of that time as my only transport with a sidecar just to really hammer the bushes, and still I have never had to do anything about them, I would leave them alone - just mask them off or at lest check with the powdercoater that his work doesn't require the swing arm bushes to be replaced. I belive bronze insert ones are reaconned to be a worthwhile upgrade, I wouldn't honestly know if mine were upgraded by a previous owner as I just wire brush things and bung on more paint with a brush.
