Here is a well preserved series 1928 $500 FRN from the Chicago district with the desirable Light Green Seal. This note is housed in a Capital plastics currency holder.
An interesting aspect of the Federal Reserve Notes from 1928 is that their redemption wording states, "Redeemable in Gold on Demand at the United States Treasury, or in Gold or Lawful Money at any Federal Reserve Bank." No Federal Reserve Note since 1928 has carried this redemption. This is an Extra Fine example that saw very little use.