My Thompson seat post and stem are 15 years old and still don't have any rust on the bolts despite being used during winter time and wet conditions. All the other bolts on all my other bikes and components have some rust on them. The disc brake adapter and caliper bolts have most rust on them even after after I've been greasing them during winter riding season. Axle nuts have no rust because they are zinc plated and i grease them regularly...It's just cosmetic rust and doesn't bother me.