EXTREMELY FINE. A BEAUTIFULLY CHOICE AND RARE UNUSED EXAMPLE OF THE 5-CENT NEW YORK POSTMASTER'S PROVISIONAL WITH THE A.C.M. SIGNATURE.
The A.C.M. initials with the periods are believed to have been written by Marcena Monson, brother of Alonzo C. Monson. In the February 1967 Siegel Lilly sale, this remarkable stamp realized the second highest price of any off-cover New York stamp, exceeded only by an original-gum example on Blue Wove. A review of Power Search failed to find another unused example in any condition.
Ex Caspary, Lilly and Grunin. With 1987 P.F. certificate