Although described as regular dies trial pieces, this was deliberately struck for sale to collectors as part of complete off-metal sets.
Examples were struck as follows:
Copper J760/P845 with fewer than a half dozen known.
Photo courtesy of Ira & Larry Goldberg's Coins & Collectibles.
Aluminum J761/P846 with fewer than a half dozen known.
Nickel J762/P847 which is possibly unique. Pollock lists only the Bowers and Ruddy 12/75 sale example. This or a second example, from Bowers and Merena's 9/2001 sale is illustrated below.
Photo courtesy of Bowers and Merena.