Although described as a regular dies trial piece, these were actually deliberately struck for sale to collectors as part of complete copper sets. The Garrett collection had one such set sold by Stacks in March 1976 and a double set was apparently stolen from the Iowa State Historical Museum.
Over a half dozen are known including one circulated example and were struck from the Dannreuther die #1. A single example ex Seavey Descriptive Catalog (1873) #1056, Parmelee (1890) part of lot 175 is known struck on a cent planchet. This is a mint error and should not be confused with the die trial. For additional information about this, click here.
Photo courtesy of Heritage is the former Garrett-JHU coin.