A half dozen highly collectible $20 FRN errors. $20 1963A FRN STAR G06589774* PMG 66EPQ Gem Unc with a thin strip of the face printed onto the back, $20 1963A FRN E15370131A PMG 53EPQ About Unc with same thin strip of front onto back right margin, $20 1977 FRN PCGS 65PPQ s/n B09866072D with 10% strip of back printed onto front, $20 1977 FRN H53869725A PMG 55 with 100% of back LIGHTLY printed onto front, $20 1977 C68678293A PMG 58EPQ, with 30% of back overprinted onto front, and $20 1981 #A66194340C PMG 58EPQ, with 80% of back LIGHTLY printed onto the front. Estimated Value $500 - 800
Remember that having these six notes graded would cost you a minimum of $200 with 2 way postage and insurance.