'UN PESO' on 2p 50c brown postal stationery notification envelope (H&G NB2) with 'CORREOS NACIONALES SERVICIO INTERIOR' overprint in black (Guatemala Handbook unlisted Type). A fine used example with partial circular 'RECEPTORIA DE CERTIFICADOS ADMINISTRACION CENTRAL GUATEMALA' cds in purple dated 18 APR 1929 on reverse. Addressed locally within GUATEMALA CITY.