SILCO Plating: Silver or Not?

[Traintime]

As a unit of International Silver Co., the Silco mark generally relates to stainless steel production of the core (base metal) of an item. Some of these, such as one-piece solid handle knives, can be found with a rather thin plating. Is this actual silver plate or some form of vacu-sealed chrome?

[Traintime]

An added bit of possibly useless info--while pounding keys I came across a listing for a carded sterling silver pendant/charm that was apparently marketed as made by Silco Products USA (c.1973). Whether this was related to I.S. Co. is not clear, but perhaps they were extending the brand name into real silver. As of late, the Silco name seems to have been co-opted by other firms.