This story is better than the 10,000 bitcoin for 2 large pizzas story from back in 2010. This story is an actual direct exchange of bitcoin for goods received...for the hamburger. The pizza story is really bitcoin payment to another bitcoin enthusiast in return for them ordering a pizza for you...it doesn't represent some unique early, real exchange for goods and services.
The coin looks clean! 1.5 BTC is quite a fair price. Someone should be on this quick!
It does have a very interesting history indeed. Erik Voorhees used this coin to pay for food at porcfest in 2012. I wasn't selling the food, but the vendor who sold the burger didn't know what to do with the bitcoin, so I gave him $7 for it. The exchange rate on Gox at the time was about 6 change IIRC.
Will update if / when it is sold.