unused Block of Four 1949-50, 1c-50c O.H.M.S. officials (O1-O9, O11, O15A, CO1, EO1), plate no. blocks of four, fresh, virtually all never hinged (5c value has some offset on reverse), no. CO1 has light selvage crease, otherwise fine-very fine lot, Scott retail as four sets of singles $1,069.00+