Lot 746, Sierra Leone 1933 Wilberforce set with curved SPECIMEN perfin, VF NH July 24, 2020January 11, 2018 by Sparks Auctions Lot 746 Sierra Leone SG#153s-165s 1933 ½d to £1 Wilberforce set with curved SPECIMEN perfin, mint never hinged, very fresh and very fine set. S.G. £850.