My feeling is that if it is a chrome or Nikasil bore, the only thing that is going to happen with a quick sanding using 400 or 600 sandpaper wet with some solvent is a removal of the oil glaze anyway. You are not going to damage the chrome unless you get really carried away. Then you might damage the chrome right at any sharp port corners/edges. That removal of any oil glaze is exactly what we want for the new ring to break in properly.

AV8TOR