James W. Tufts plaque... for what?

I found this at an estate sale last weekend. I had no idea what it was for when I bought it, but was intrigued by its size and weight. I don’t have it in front of me right at the moment, so my measurements aren’t precise, but it’s about 5 - 6 inches wide, about 2 - 3 inches tall, and about a quarter inch thick, weighing in at 1.1 pounds. It does seem to be silver plated.

A friend suggested it might have been the makers mark screwed onto a box of silverplate flatware from the late 1800s. Does that seem correct?

Correction to my previous post. The dimensions are:
7.5 inches x 3.3 inches x 3/8 inch

Most recent speculation is that this plaque may have been attached to one of Tuft’s other businesses, as he manufactured soda bottling machines and carbonation machines.

The mystery continues…