Congratulations!!
I remember my first seated. It was on a New Year's Day that was unbelieveably warm so I went digging at a construction site I'd hit several times. When I picked it up I thought it was a Barber by looking at the back. Boy was I thrilled to see that lady sitting on the front! It was a long time until I found another one so I really cherished it!
And when you dig a silver coin that's been under concrete they can look like just about anything. The chemicals/salt etc. do weird things to silver coins. Looks like yours cleaned up well. A little electrolysis would take the rest of that dark off if you want to go that far. Looks good to me like it is though!!!!
Neal