No the stamp with .925 or other Sterling halmark would be on the outside of the scales.
I think it is probably a real diplomate, looks like it from the picture.
Maybe Lund did the polishing on these, Lund did make some of the Sterling models for Victorinox.
Victorinox appears to have been clearing inventory of the diplomate lately as it has appeared at a few retailers at discounted prices, so unless someone made a mistake it is very likely you have the polished stainless steel Dimplomat.