VERY FINE. THIS IS THE UNIQUE PAIR OF THE 1917 12-CENT PERF TEN AT TOP OR BOTTOM ERROR, AND CONTAINS TWO OF THE FOUR RECORDED UNUSED EXAMPLES. A GREAT 20TH CENTURY ERROR RARITY.
This pair comes from what was once a block of four containing two error pairs. The other pair has been separated into two singles (due to one being faulty). Our census of Scott 512b, available at our website at https://siegelauctions.com/census/us/scott/512b , contains only 16 used, one on cover and four unused examples of this rarity, including this unique pair.
Census No. 512b-OG-PR-01. With 1980 P.F. certificate for the block of four