no, but mask off the bore just to be safe, especially if your sand blasting which is more aggressive than bead blasting. i use a special Nashua?? brand duct tape. its very expensive but its what the professional sandblasters use and they say its the only tape that doesnt blow off or get effected by the jet of sand. for beadblasting i sometimes stuff the bore with newspaper and block off top and bottom with normal duct tape. if your going to rebore it anyway it wont really matter if you get some of the bore blasted from overspray