I would personally pass. So many out there, you can get a lower price. Edit: reverse and obverse do not seem evenly toned. Definite pass for me.
Really, in my opinion, the color is off, not right for a perfect cir-cam. Like it was lightly cleaned, then spent too much time in a paper envelope.
A Thorn head would be the name given to a certain die pairing, they are called VAM's. From what I read the "Thorn head" has been broke down into 11 different die states.
I'm not really into American coins but I've found loads of graded ms60-63s for sale around the £40 area
I can't tell for sure if it truly is a thorn head but if it is I think it could only be a 1B2 which is not one of the most common die states.http://www.vamworld.com/1921-S VAM-1B
Thanks all for the input. It was one of those I glanced at right before I went into work. Glad I let it go.