If the barrels have been sleeved,it is likely they were blued by the same person.If this is the case, it is also likely he either used a solder not affected by the salts, or a bluing method that wouldn't affect the solder.Anyone skilled enough to sleeve the barrels would understand the problem.If this were my gun,I would proudly use and enjoy it without worrying about the ribs,until such time as they actually start comming loose(if they ever do).
Mike