Most likely ex Pittman. Virgil Brand - New Netherlands 12/1958:359, $75 - John Jay Pittman - David Akers 10/1997:448, $2,200
Ron Guth: Breen (1989) listed Proof examples of LM-1 and LM-2.
Logan and McCloskey (1998) discounted both varieties as Proof candidates because both were struck from used, worn, or cracked dies. In fact, they did not list a Proof for any Half Dime variety, giving the implication that Proof 1836 Half Dimes may not exist in reality.
PCGS has graded one Proof 1836 Half Dime, believed to be ex-Pittman.
Sources and/or recommended reading:
"Walter Breen's Encyclopedia of United States and Colonial Proof Coins 1722-1989, New Revised and Corrected Edition" by Walter Breen (1989).
"Federal Half Dimes 1792-1837" by Russell J. Logan and John W. McCloskey (1998)
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