Need Asistance 8 Reales Mexican True Or False?

Thanks for the help, do you know about the cost in dolars aprox?

The coin on the bottom is a 960 Reis of Rio De Janeiro struck over an eight reales host. If you look carefully around the legend you may see traces of the under-coin's legends, enough to place its mint of origin, and sometimes even its date. It is in high grade and the nicest of the three. The middle coin looks to have issues, either environmental erosion, cleaning, and contact with PVC from being in an old coin album (green residue), or it could be a cast copy as the reverse seems to lack detail and the silver is too bright for my taste. The top coin from Potosi, Bolivia appears genuine, but has significant wear.