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 J1102/P1238 with only 4 or 5 are believed to exist including the illustrated example above courtesy of Superior.
Aluminum J1103/P1239 with only 2 or 3 believed to exist.
Nickel J1104/P1240 with only the Newcomer, Lohr coin believed to exist. It was last offered in ANR's 8/04 sale and is illustrated below.
Photo courtesy of American Numismatic Rarities.