Description and research notes
Final plain-issue example within the 1887 Banco Nacional 20 Centésimos series, prefix K, showing the mature Waterlow & Sons plate. By this time, branch overprints had ceased and new deliveries from London circulated unmarked. Mercury vignette identical; slightly greener paper and deeper black lines show re-inked presses.
Serial K078922 carries the same officials’ autographs in lighter hand, suggesting high-volume signing near the end of production. Cataloged Pick A88a / PMG A88a (Plain Issue). Fifth and final in the 1887 sequence, it closes the narrative from plain origin through branch validation and back to uniform distribution.