Metallurgy Question:

There is no physical distinction between these two grades of stainless steels since there are very similar compositionally. However, it might be possible to differentiate them rapidly by comparing their electrical resistance (measurable via an ohmmeter), indeed with some considerations in order to minimize the errors. I assume you already know that the most reliable method of telling them from each other would be to perform a chemical analysis of them using EDS and other spectroscopy methods.