1 Peso Pattern, Guerrero Aguila, Uniface, Brass

Pattern coinage from the Casa de Moneda de México in this period reflects an aggressive modernization program the mint undertook in the late 1970s, testing new alloys and planchets in anticipation of rationalizing Mexico's fractured circulating series. The uniface strike indicates this was an early-stage die trial — one face impressed, the reverse left blank — used to evaluate relief, metal flow, and die wear characteristics before committing to full production tooling.

The "Guerrero Aguila" designation distinguishes this eagle type from concurrent variants tested in the same program. It never entered circulation.