That's a good eye.  It's the right style, but I think it is a reproduction.  That's not totally out of the question, but it appears to be a reproduction of the later version.  Quick check for this one is the visible seam in the ring.  You won't see one on an original.  This could turn out to be the classic example of finding one too soon after you decide to look.  You find one right away and then don't see another for a long time. 

I will probably pass on this, but I really appreciate you mentioning one for sale.  Thank you!!