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SIERRA LEONE - 1964-66 NEW CURRENCY 7c on 1s3d sepia & emerald-green, SG 322, a never hinged mint vertical block of 8, showing the GRADUAL OMISSION OF THE SURCHARGE - four stamps have varying degrees of missing surcharge with the bottom right stamp with SURCHARGE OMITTED variety, SG 322a, a stunning display piece. (8 stamps)