I have never heard of any type of steel being non magnetic. Steel itself is a ferrous material, the plating on top of the steel should have no effect on its magnetic properties.
Anyone able to confirm this? I can't.
Stainless steel is NOT plated. It is a different metal throughout. There are 3 'breeds' of corrosion resistant steels. One is a little magnetic, but nothing like tool steels. The other two are not. Ask an airplane mechanic.