Although described as regular dies trial pieces, these were actually deliberately struck for sale to collectors as part of complete off-metal sets.
Examples were struck as follows:
Copper J692/P771 with about a half dozen known.
Aluminum J693/P772 with about a half dozen known.
Nickel J694/P773 with about a half dozen known including the example illustrated above.
Nickel but with a plain edge J695/P774 with only the Stickney (H. Chapman 1907 lot 548), Brand (journal #39029) coin known and it has not been seen in almost 100 years. It is not known whether it was struck using a plain edge collar or some sort of broadstruck mint error.
Photos courtesy of Superior.