Although these are described as regular die trial pieces in the standard references, the off-metal 'trials' of this year were deliberately struck for sale to collectors.
They were struck in the following combinations on both thick and thin planchets.
Copper J1020/P1155 with about a half dozen known including the illustrated example courtesy of American Numismatic Rarities.
Aluminum J1021/P1156 with at least 3 known, Simpson's, Queller's and Denali's.
Nickel J1022/P1157 with fewer than half dozen known. These were struck from both proof, AW849, (date high and to the right of the point of the shield, per Ron Guth) and business strike, AW850, (date lower; 1 below the point of the shield) dies as shown below courtesy of PCGS.
It is one of the few die trials known to exist in both formats.