Definitive stamp perforated "OFICIAL" for use on external mail sent from government offices in Guatemala City. The perfin was applied to stamps requisitioned from available stocks, so the issue date given here is approximate.
The perfin may exist upright, inverted, reversed and reversed inverted. Forged perfins may exist.
Footnoted in: Stamp Number, noted in 2009 but not in 2021, although the latter edition mentions that any 1912-1926 Guatemala stamps may exist with this perfin.