Although these are described as regular die trial pieces in the standard references, the off-metal 'trials' of this year were deliberately made for sale to collectors.
Examples exist in the following combinations:
Copper J1167/P1309 with fewer than a half dozen known.
Aluminum J1168/P1310 with only 3 or fewer believed to exist.
Nickel J1169/P1311 which is unique and ex Woodin-1914 ANS exhibit, Newcomer, Farouk, Pine Tree 9/74, Paramount 4/77, B/R 6/79.
Photo courtesy of Superior.