Although described as regular dies trial pieces, this was more likely deliberately struck for sale to collectors as part of a complete off-metal set.
Examples were struck as follows:
Copper J924/P1029 with fewer than a half dozen known including the illustrated piece courtesy of Superior.
Aluminum J925/P1030 with only 2 known including the illustrated obverse below from Steve Ivy's 10/77 sale. An example ex Simpson-Heritage 9/20 - PCGS64 appears to be a second piece.
Nickel J926/P1031 with only the former Newcomer, Lohr, Simpson - PCGS66 example known and illustrated below courtesy of PCGS.