BELGIUM. Royaume de Belgique Tresorerie. 50 Francs, 1966. P-139. PCGS About New 50 Apparent. Discoloration. Serial Number One.A Block. An astonishing offering for this 1966 Belgium piece with an A Block Serial Number 1. The full serial number 0001 A 001 makes this piece even more appealing. PCGS mentions Discoloration on the holder but it is our opinion that is a negligible comment when taking into account the Serial Number, and the fact that all the detail of the note still remains, and the hues are easily distinguishable.