Dale - Those seem to be the coordinates for Pico del Aguila, a lower subpeak of Cerro Ajusco. The coordinates that I measured by GPS are:
Cerro La Cruz del Marqúes - N19 12 27.2 W99 15 29.4 - 12898 ft (3931 m) - The actual highpoint
Pico del Águila - N19 12 46.8 W99 15 25.2 - 12776 ft (3894 m)