As TJ said, they will continue to work provided there are no dents/dings in the stanchions.
Suzuki motorcycles made a lot of noise a few years ago when they released their GSXR range of sportsbikes with DLC forks....Diamond Like Coating.
Think Kashima coating for the MTB equivalent and you get the idea....except DLC was black not gold....anyway, very quickly the coating rubbed off these DLC treated stanchions and looked awful....but testers/journos found no discernible drop in performance and its now just accepted that if you buy a GSXR with DLC forks then the front end of the bike will look like it has leprosy....but it will ride fine.
....needless to say Suzuki dropped the idea pretty quickly and their fork stanchions are back to being bare metal, afterall if there is no coating on them to begin with then the public cant moan about it coming off!