My Mother's old brooch

This brooch was in one of my mother's boxes. She died 10 years ago and would have celebrated her 103rd birthday if she was alive. Which suggests to me the brooch is old. What is puzzling is that if you look closely at the duck, it looks like it was produced by a dot-matrix printer, which I doubt were not around when Mom bought this. The base looks and feels like it was a shell, but I can't be certain.

Thanks for any thoughts.