The Canal Zone Postal Service issued the 15-cent Gamboa- After commemorative (Scott 131), one of stamps in the Twenty-fifth Anniversary Series, on August 15, 1939. Along with fifteen other stamps, it is part of two groups of eight 'before' and eight 'after' scenes of important Canal Zone areas and facilities.
The scene strongly resembles that on the 14-cent stamp. However, by the time this shot was taken on December 22, 1922, electric pylons ran along the Panama Railroad tracks and the Gamboa Dike, destroyed on October 10, 1913, by President Woodrow Wilson, was gone. The dike's destruction allowed the waters of the Chagres River to flow into the Gaillard Cut. A pair of steamers plies its way through the Canal, and a train heads towards Cristobal, the Caribbean port city.
The 15-cent stamp covered first class postage to the United States, parts of Latin America, and parts of the Caribbean. This rate also applied to a minimum fee registered letter. It was relatively successful in terms of sales compared with the lower values. Of the 313,200 copies printed, just over 105,000 sold. Postmasters took them off sale on February 28, 1941. Officials destroyed the remaining 208,000 copies on April 12, 1941.
Patrons used the stamp on airmail letters when they chose not to use the Twemtu-fifth Anniversary airmail stamp intended for that purpose. It appears on a great variety of first day covers. In addition, collectors saved many unused copies. Since fifteen cents paid the minimum registry fee at the time, it appears on covers using that service. In addition, patrons used it with other stamps, and it appears in non-philatelic usages as one of a group of stamps on a cover or packet. Despite its relative frequency of use, it is still scarce on cover.