This is a New Orleans mint reverse die trial struck in tin from a rusted die.
It is not in any of the standard pattern references despite it having a long pedigree. It is ex Haseltine 7/1875, Scott Stamp & Coin 12/1877, S.H. & H. Chapman 2/03, McCabe (S.H. & H. Chapman 6/1905), Brand (journal #29415), Armin Brand, consigned to BG Johnson on 10/27/1936, Terrell-Bowers and Ruddy 5/73, Heritage 95 ANA, Superior 1/96.
We believe it should be assigned JA1841-1/P3084 based on how Judd & Pollock assigned their numbers unless someone can tell us which year this reverse die was first used.
Photo courtesy of Heritage.