In the 2011 April Rosemont CSNS Platinum Night US Coin Auction, Heritage Auctions offer several very rare proof bust halves. One of these is the sole known proof 1823 half dollar from O-111 dies, though a handful of O-108 specimens are accepted as proofs to varying degrees.
This is one of the few proof coins Walter Breen admitted to not having examined in his legendary Proof Encyclopedia, where he wrote:
"Normal date. Repeatedly reported but not seen by me, though several deceptive early strikes are around. First auctioned in the J.N.T. Levick sale of October 1864 (W. Elliott Woodward, auctioneer), Cleneay:1154, illustrated; several flat stars. Waldo Newcomer had one, #1440 in his private catalogue, unattributed, possibly the Levick (?) - Cleneay coin; it cost him $25 back in the early 1920's, which was then a high price even for proofs."
Interestingly, Breen did not record the offering of the present coin by B. Max Mehl in November 1954, as lot 230. From there it went into the Norweb Collection, later to be offered as lot 3079 in Norweb III in November 1988. This piece was linked speculatively to the Levick - Cleneay pedigree mentioned above by Breen in both its Norweb appearance and its initial Heritage appearance (see below), and the absence of other examples of the O-111 as a proof make that descent the most plausible, though there will always be a measure of uncertainty where the coin was before the Mehl auction.
Heritage offered this piece in its January 1996 FUN Auction, and will once again do so in the upcoming Platinum Night on April 28. Last time the coin was described by the cataloger as follows: "This piece has exceptionally deep mirrors in the fields with quite a different 'look' to it than a prooflike business strike, even though several of the peripheral stars are not fully struck. Both sides show light golden toning, and the devices have a moderate amount of mint frost which provides a modest contrast on each side."
The presence of a few flat stars is a constant refrain in the descriptions of the proof O-111 1823 half dollars throughout history. More subtle visual markers that turn up in the Norweb and Heritage 1996 plate appearances include a tiny dark toning dot at the back of Liberty's cap and two areas of planchet roughness on the reverse, one on either side of the eagle's neck. Though lightly hairlined with a pinscratch trailing from the M in AMERICA, this is a fundamentally pleasing specimen that will prove to be a star in whatever cabinet of early U.S. coinage holds it next.