ROBAR has done this treatment very well. Critical to the process is proper passivation (etch) of the "raw" stainless surfaces, and then they tumble in a ceramic/poly mixture, followed by a specific oven curing. Then a buffing brings out the soft gloss.
Ruger's process actually & measureably increases the corrosion resistance over the stainless properties.
Of course, they can also completely black-oxide the SS gun & rings for a truly unique SRH!