VENEZUELA. Lot of (2). Banco Central de Venezuela. 10 Bolivares, 1945-60. P-31fp & 31bp. Front & Back Proofs. Uncirculated. This pair of front & back proofs contains the locations of the hidden code letters, used to deter counterfeiting. A neat piece of the design process, and a piece which only becomes available when large collections are broken up. From the Rosenman Collection.