Watch List notes:

Costa Rica, 1 colon, 1923 counterstamp (Type VIII) on a Costa Rica 50 centavos, 1890GW, NGC MS 64, c/s UNC standard, finest known in NGC census. KM-163. Full and pristine countermark on a choice-grade host with luster throughout, incipient reddish toning, just some light wear and marks on the "bottom" side relative to countermarking (hence probably from the act of countermarking itself and not from actual circulation), the finest known at NGC by six grades. NGC #4738959-015.

Estimate: $125-200