It is usually a bulk property though you would need to know exact regulations for your country to be certain.
Stainless steel is steel (i.e. iron + a little bit of carbon) alloyed with another metal (usually chromium) which makes it resistant to oxidation by atmospheric oxygen (usually chromium). It does, but not mean though that it would resist to strong acids (e.g. concentrated hydrochloric acid) or strong oxidizers.