Just viewing the KS7 preview and I couldn't see 'Stainless Steel' in the materials list.
Is it lumped under 'Steel'?
The Metal presets contain measured data of mostly pure metals.
We do have a preset for brass. Unfortunately this data is very hard to find for any other alloys, including the many varieties of stainless steel.
The KeyShot Library will have a large number of updated brushed metals that can be used as a basis for stainless steel.
E.g. brushed iron with some anodization is a viable way of simulating tempered and stainless steel.
Dries