Looking at the Red book, a 1920 (D) isn't worth much until you get to About Uncirculated or Mint State. A weak "D" for this year is not listed. Now, on the other hand, a 1922 "No Mint Mark or Weak Mint Mark" carries a decent premium. No "D" starts at $600.00 in G4 condition or $35.00 for a weak "D" in G4 condition. This may be the wheat your thinking about...1920's are pretty common...Cheers