This is a series I collect. First thing I look for is if the vertical lines in III are all or nearly complete and yours appear to be. 1866 is the second highest mintage so it’s not a rare date. I think all the odd denomination coins are interesting. My knee jerk reaction is a solid $35.00 coin.... But the surfaces appear pitted or something. Maybe pixilation in the photo?
I once had an 1878 XF disturbed proof. All the lines in III were sharp and distinct with no or very little wear. Only 2350 minted. It was given to me by my grandmother. Where she got it, I haven't a clue since she didn't come to the US until 1923. Anyway, I sold it in the early 1980s for $900 to buy an engagement ring for a girl I ended up breaking up with and not marrying....A tale of a great coin gone down the porcelain facility...live and learn
Definitely genuine but the surfaces do appear to be suffering. I do think it's been cleaned and maybe that's why it looks the way it does.