In that top condition, the 'coin' looks suspect to me.
It should be nearly 26.75 not 25 grams (if I'm readying your scale correctly) and the assayer's initials should be FM, not II.
What is your history with this piece? Inherited, dug or purchased?
Don.....
I believe the edge reeding looks way wrong from any 8 Reales I've ever seen. I don't think that the 1801 should have vertical edge reeds, but rather I believe they should look more like:
(Not my picture)
Although I'm not sure exactly what the reeding style is for 1801 Mexican mint pieces are.
It is a cast fake. And not a good one. For fun, you can actually trace the hairline on Charles head as it is a continuous cast line like child's maze puzzle.