Mysterious Mark on Tray

[lamonnier]

I have a silver tray with handles. The handles and trim are very ornate with lots of engraving on the tray. It is approx. 22"x12" and very heavy. The only marking on the bottom of the tray is YZ71-7. It almost looks as though it was engraved by hand.

I was hoping that someone could tell me who the maker is.

If I am not on the correct message board please let me know where to go.

Thank you.