Chad 1978 25th Anniv of Coronation opt'd in silver on Silver Jubilee 450f (ex m/sheet Philippe French spelling) imperf proof mounted on Format International proof card, as SG MS528
Chad 1978 25th Anniv of Coronation opt'd in silver on Silver Jubilee 450f (ex m/sheet Philippe French spelling) imperf proof mounted on Format International proof card, as SG MS528