This is the regular dies trial piece struck in copper. It is the first off-metal die trial for a dollar ever struck. It is likely to have been deliberately struck for sale to a collector as opposed to being struck to test the dies.
This piece is possibly unique with all its auction appearances - Cogan 10/1865 (F.S. Edwards), Cogan 10/1875 (Col Cohen) to Parmelee (6/1890), Woodin-1914 ANS exhibit, Newcomer, Farouk, Kagin's 77 ANA, Ivy 12/81 likely representing a single example.
Photo is a composite and is courtesy of Heritage.