Although these are described as regular die trial pieces in the standard references, it is more likely that the off-metal 'trials' of this year were deliberately struck for sale to collectors.
Examples were struck as follows:
Copper J1026/P1161 of which fewer than a half dozen are known
Aluminum J1027/P1162 with fewer than 3 known including one in the Simpson collection
Nickel J1028/P1163 which is believed to be unique and is ex Woodin-1914 ANS exhibit, Newcomer, later to Simpson-Heritage 9/20 - PCGS64 and is illustrated below.
Photos courtesy of PCGS.