This is certainly a nice coin and the only one I've seen in this grade(so far). For brass, it's very good.

However, please spare us some agony and have a clue about the current market, especially noting the difference between the price of BTC in July 2013 when this was sold and now.  Back then 1BTC was around $90, and now it's over 3x that.  

I'd estimate the market price should be about 6.5BTC for it, based on current BTC value as well as the fact that MS-66 versions command roughly 5BTC in today's market, and MS-65 can be had for under 4BTC  Granted a 67 for brass is very good, but grades have been coming back higher lately so this most likely will not soon be the only of its kind.

Edit: and you're right AT, I didn't originally notice the mark on the B.  Hopefully it's just a mark on the slab, but if its on the coin this should be a much lower grade, and my 66 should then be a 68...