29c x 20, Legends of the West Issue 1994, Error Sheet. Scott No. 2870, Issue Copies - 150,186, Issue Year - 1993.
The facts surrounding the issue of this sheet of stamps make for one of the biggest stories ever in error-stamp collecting.
The portrait featured on the Bill Pickett stamp is not that of the famous rodeo cowboy, but that of his brother Ben Pickett. This portrait has apparently been confused with Bill Pickett’s in other sources as well.
The mistake was discovered by Pickett's great-grandson Frank Phillips Jr., who learned of the stamp when a radio reporter contacted him for comment.
Although the design error was discovered before the First Day of Issue, 183 sheets were mistakenly sold by postal workers!