Greenock, a Mexico, Ferdinand VII, 8 Reales, 1821rg, Zacatecas, obv. countermarked j. mck · & Son greenock around 4/6, 26.92g/12h (Manville 58, and p.114, this coin not listed; D 100; Seaby ST 57). Coin fine and toned, countermark good fine (£500-700)

Provenance:
Acquired by the vendor in 1977.

Manville lists three others for 1821 Zacatecas (SNC June 2002, p.117)