Don't do anything to the stock if it doesn't need it. If the wood just appears dry, use a 50/50 mix of BLOicon and turpentine. It won't build up and will liven up the wood. Less is more.
The 4/0 steel wool will work much better than nylon bristle brushes. The rust itself is probably the most abrasive, so the longer you scrub it the more chance you will remove finish. Oil the rust down and let it set a few days before attempting to remove it. Rub lightly with the 4/0 steel wool, and wipe often with a cloth to remove the rust as it is loosened.