MEXICO. Cob Real, ND (1554-56)- Mo O. Mexico City Mint. Carlos & Johanna. PCGS Genuine--Environmental Damage, EF Details. KM-9; Cal-75. An enchanting early Mexican minor, this piece displays bright pearl gray devices with some charcoal patina that has redefined the reverse surface texture enough to cause a details grade from PCGS. Nonetheless demonstrating eye appeal well in excess of what can usually be expected from the designation and sure to achieve a strong bid.