Air Post stamps. 1929, Eagle, imperforated proof of 25c in green and brown, horizontal pair, nice four-side margins, full OG, LH, VF and scarce, only 50 stamps were produced, Sanabria #14, C.v. $600 (1966) (Image)

Official stamps. 1927, inverted black overprint ''Oficial'' on Post Office 5p green and black, full OG, previously hinged, VF, MEPSI certificate, the stamp is listed, but has no price in Scott Cat. (Image)