This is huge news, since there were only two known examples of the 1835 LM-12 half dime prior to discovery of this piece. No doubt the coin will attract some healthy attention at the Stack's auction. The coin is in the Stack's 15-16 June 2010 auction in Baltimore, MD.
Editor's Update: Price realized (with buyer's premium) was $6,900!
July 24 editor's note: PCGS graded the coin VF-35 and put the attribution on the label as "LM-12, Small Date, Large 5C"