Although described as regular dies trial pieces, this was more likely deliberately struck for sale to collectors as part of complete copper sets.
T. Harrison Garrett had one and a double set was apparently stolen from the Iowa State Historical Museum.
About a half dozen are known.
An example listed in nickel as J603/P668 has not been confirmed likely does not exist. We believe the listing in Adams & Woodin for AW602 was meant to be copper.
Photo courtesy of PCGS is the former Garrett coin.