Not a clue about these, but given the abdication date it doesn't sound right. What mint is it? Weight? Edge?
The portrait doesn't seem to match the 1808 coins exactly, but I haven't checked all the different mints. The eyelid is too long for a start and the front cuirasse strap could be a bit too long. Usually the other 3 are slightly longer.
It's almost certain the Chinese will be making these, so anybody know if this is one?
You might be better off posting on a US forum as there are a lot of collectors of 8 Reales over there due to the Hispanic connection with the US. If it is a copy, it won't be the only one.