$20 1977 FRN BLANK BACK ERROR Missing First Print PMG Gem Unc 66EPQ

A seemingly perfectly-preseved $20 Blank Back error that's remains fully-original. This $20 1977 Federal Reserve Note failed to receive the first (back) printing while the remaining impressions were applied as intended before it was cut with even and generous margins and released from the Bureau of Engraving and Printing.