Although described as regular dies trial pieces, these were actually deliberately struck for sale to collectors as part of complete sets.
Examples were struck as follows:
Copper J784/P869 with about a half dozen known.
Aluminum J785/P870 with about a half dozen known.
Nickel J786/P871 which is believed to unique and is ex Woodin-1914 ANS exhibit, Newcomer.
Photo courtesy of Heritage.