Vtg Mid Century Los Castillo Mixed Metal & and 43 similar items

Interesting plate acquired recently at an estate sale. Appears to be mixed metal of silver, brass and perhaps copper with feather plumes used along with a resin to create a piece of glass art inset in middle of 6 inch (across) plate. On the back side there are two coins inside the glass/resin. One says PLUMA AZTECA and the other HECHO EN MEXICO 583. On the underside rim of the plate is marked LOS CASTILLO TAXCO HECHO EN MANU MEXICO with the #50 and a ?1? inside the circle of the phrase. The assumption is that the resin was made by one artist and the plate by another but not positive. As this is collected fairly widely, I am sure someone will let me know if I have missed anything. I do not believe this is silver but there may be some silver content but no real way without destroying the piece. It?s too interesting to do so. Plate weighs a total of 8 ounces on our scale. Will ship USPS first class with tracking to winning buyer