Although described as regular dies trial pieces, this was more likely deliberately struck for sale to collectors as part of a complete off-metal set.
Examples were struck as follows:
Copper J775/P861 with about a half dozen known.
Aluminum J776/P862 with about a half dozen known.
Nickel J777/P863 with only the former Woodin-1914 ANS exhibit, Newcomer, Farouk, 76 ANA, 78 ANA example believed known.
Photo courtesy of Stacks.