I'm not sure about the authenticity of the 1776 coin. I think there have been several images of similar coins posted here that were cast copies or fakes. Don't take my word for it. Maybe someone who knows more than I will chime in. Chris
The Mexican 8 Real is fake. The wear on the the reverse is inconsistent, only some of the high points are worn, but other are not. On the obverse the lines on the copy are just too sharp when you compare it to the wear on the portrait.