Although described as regular dies trial pieces, these were actually deliberately struck for sale to collectors as part of complete off-metal sets.
Examples were struck as follows:
Copper J1452/P1599 with only 2 examples believed to exist. One is supposedly ex Woodin-1914 ANS exhibit, Newcomer, Boyd, Farouk, Merkin 9/67, Stacks 6/86. Another or the same coin prior to Boyd is ex Dunham (Mehl 6/41), Olsen (Mehl 11/44).
Nickel J1453/P1600 which is unconfirmed and is likely a misdescription of the 1876-CC J1453B/P1602.
Photo is a color enhanced regular issue proof. Photos used are courtesy of Heritage.