MEXICO. Brass Uniface Peso Obverse Trial Strike, 1979. Mexico City Mint. PCGS SPECIMEN-65. PL-145A (RRR). Variety without mintmark. By R. Luna Vasco. One of just seven of this <strong>VERY RARE</strong> uniface trial striking seen at PCGS, the present Gem shimmers with intense brilliance and luster, with a particularly mirrored sheen to the fields on the obverse.