Fr. 2402. 1928 $20 Gold Certificate. PMG Extremely Fine 40. Obstructed Print Error. Any and all errors on Gold Certificates are rare and this example is tremendous in every way. This $20 is found with an obstruction error. An obstruction during the third printing resulted in the entire gold seal and most of the serial number, save for a full letter and number and a partial letter, missing on the left end of the note.