Pierced Silver Nut or Bon Bon Dish

This is a really cool little plate.It appears to be hand tooled as the piercings are bent through the back side of the piece and the stamped pattern appear in reverse on the back side. My first impression was that it was solid silver vs. silver plated and my gut tells it is. It is non magnetic and there is no sign of the silverplating ( if thats what it is) wearing through. What's got me stumped is the "hallmark" if you can call it that. See the picture. All it has is the word "silver" stamped or engraved on the back in the center. I have spent hours trying to find a reference to that simple mark with no luck. Can anyone help me find out more about this neat little plate?