I have always loved that particular plate and would love to dig one myself. Yours is a beautiful example. But I have to tell you it is post War of 1812. I don't have my book on me but I'm pretty sure it's 1820s.
Well you can be pretty well assured that your site hasn't been detected before.
Congrats on the awesome looking plate and coppers. All the finds have that beautiful patina that makes everything look all that nicer.