Heritage has sold a few, but very little is mentioned about diagnostics etc. Any info would be greatly appreciated.
There was a commemorative half dollar known as a new rochelle. It is my understanding that 50 of them were made from as presentation pieces. Here is a link with some more information: http://www.coinfacts.com/commemoratives/half_dollar_commems/new_rochelle.htm
According to Breen & Swiatek (The Encyclopedia of United States Silver & Gold Commemorative Coins 1892 - 1954) 50 presentation pieces were struck on proof planchets with a single strike using polished dies. These were struck for coin collecting members of the New Rochelle Commemorative Coin Committee (a group that supported this Commemorative Half). The presentation pieces were distributed in small, dark red presentation boxes and were accompanied by a bronze medal. The presentation pieces will appear Prooflike (due to the proof planchets and polished dies) but are not Proof (due to the single strike). It is also estimated that 10 to 14 Matte Proof versions were struck. Hope this helps.