It exhibits large bulbous serifs and rounder center loops than found on the Ty-1. They are used here with his permission. Total Comments 1979P,D,S Unc. Several private firms created these first Day covers. Some types of errors that are available with a little searching are off centers, clips, blanks, broadstrikes, etc.
Error coins create a fun challenge and add tremendous interest to ANY collection.
It is my opinion that these coins carry no premium over face value due to their alteration.