Scotty11, there's no such thing as "artificial toning." That's a purely arbitrary term, and it doesn't exist. I know, I know, there are a lot of people who believe otherwise. I'll remind you there were a lot of people believed in the existence of witches, too. So much for that.
That coin was cleaned at one point, and it took on tarnish, and tarnish is natural. I see wear on it. AU-50/55 looks like a good grade on it.