Beautiful coin and great find! Again, we are dealing with photographs, but from them, it looks to be AU57 to Unc, most likely the latter. Now, I know you stated you didn't clean it, but NGC or PCGS may make it a Details-Improperly Cleaned coin. Note how the tarnish appears that it has been rubbed in places. I was frustrated when I pulled a beautiful Seated dime from the ground. All I did at home was place it under running water. I was banking on XL #, but it was returned from NGC as XL Details-Improperly Cleaned.
Again...Great Find!
aj