Liberia, 1938, 3¢-$1 Airmail Issues Complete, Imperforate. With "Proof" overprint, blocks of 4, o.g., never hinged, all with full margins, fresh and pristine, Very Fine, a choice and rare set of blocks, with only one sheet of each value produced in imperforate form and usually being this overprint. Scott No. C4-C13 vars.  Estimate $500 - 750. $0 (Image)