Although described as regular dies trial pieces in the literature, these are believed to have been deliberately struck for sale to collectors as part of complete off-metal sets.
Examples were struck as follows:
Copper J993/P1123 with about a half dozen known.
Aluminum J994/P1124 with only 2 or 3 known including the illustrated piece from Heritage 1/04 sale and the Denali collection. See also Scotman's 10/04 sale which may duplicate one of these.
Nickel J995/P1125 with only the Anderson-Dupont, Bergin-Stacks 6/84 piece and possibly the following piece confirmed.
Copper-nickel J995A/P1126 with only the Brand?, B.G. Johnson (offered to Boyd on 7/16/41 invoice), Boosel-RARCOA 4/72, Heritage 12/90 coin known. It is likely that this is a toned nickel example as opposed to being struck on a planchet similar in composition to an 1857-1864 cent.
One of these last 2 is ex B.G. Johnson, Kosoff in 1945 as noted in the Newman Numismatic Portal listing of invoices.
Photo courtesy of Heritage.