Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Mexico - 1922, Eagle in Flight, imperforated trial color proof of 50c in yellow and black, block of four printed on paper without watermark, overprint ''Muestra'' at top left of each stamp, full OG, NH (bottom stamps) or hinged, VF and scarce multiple, Est. $500-$600, Sc. #C1