A real coin, from this very common series, in this condition, is worth about 10 to 15 cents tops. For that reason alone I doubt this is a cast coin. This poor little fellow has been through hell, probably under acidic water actually for a thousand years and now he has to suffer the public humiliation of being accused of being a fraud? Poor little coin! Now I know you see a seam. But look at the coins below. If that border, natural to the coin, was horribly corroded for 1000 years might it look like a casting seam?