Found this copper Spanish 8 real yesterday. 1819 date with Mexico mint Mark. It appears someone tried silver plate it and pass it off as a silver coin.
1970 COMPASS-
WHITES SILVER EAGLE-
WHITES DFX, 4X6DD COIL, 6X8DD COIL, 950 COIL, 10X12SEF COIL-
GARRETT PRO POINTER AT, GARRETT AT PRO , MINELAB EXPLORER SE with 8.5x12.5 Cors coil
Just thinking out loud here, as it seems very well made, official looking, I wonder if it may be an OMS ? (off metal strike)
Quick search didn't find any, but that don't mean it can't be either...?
I have examined a silver 8 reals from this period before and it was lozenge shaped from being turned and pressed between two round rollers. If it is a regular round, it may have been minted differently or cast up. If it is slightly distorted, then it was either cast off an original or is some sort of off metal strike.
It doesn't really look cast, but you can get some decent detail with a lead-tin-copper alloy if you know what you are doing.