Although described as a regular dies trial piece in aluminum, these were actually deliberately struck for sale to collectors as part of complete sets.
Examples were struck as follows:
Copper J1045/P1179 with fewer than a half dozen believed to exist. At least one of these is a business strike - possibly a mint error on miscut cent stock.
Aluminum J1046/P1180 with only 2 or 3 believed to exist.
Photo courtesy of PCGS.