Auction 333-341 Nigeria, Cameroon, Sudan & Worldwide Postal History - Day 4

1935: 2½ pi. in green on Airmail 5 pi. black & green, variety "overprint green instead of black", used, cancelled to order, fresh and fine appearance. Very fine and unusual. Unlisted. Cert. BPA (1954) which states "the overprint appears to have been made from the original type.." Come with a normal example for comparison. Note: There is no evidence to known if this is a genuine error, trial or a philatelic fantasy.