Help identify maker - Taxco fish skeleton, mark FD / PD

[greengavin]

I have a fish skeleton pendant - non-articulated, 5 arcs of increasing size attached to spine of triangular profile, hanging from tail end with a flat, side-view head with single very small punched eye and rounded cut-in mouth suspended below.
Mark is on the chain loop and consists of an eagle containing "3", and a circle of text "TAXCO 925" above and "HECHO MEX" (indistinct) below. The centre of this circle is initials "FD", but not the conjoined initials of Fred Davis. Could be PD.
Any suggestions on maker or age? regards Gavin.