This is the completed reverse die trial of JA1857-8/P3152, in copper, of a Heraldic eagle design by Anthony C. Paquet. It was never combined with any obverse.
Because of the similarity of the eagle with JA1857-7/P3149, Judd & Pollock list this design under 1857. It is possible that this was actually produced circa 1861. For more on this, see page 175 of Bowers & Merena's March 1980 Garrett II sale.
For additional information on this, please refer to the article on the 1861 Paquet dollars in the ANA Centennial Anthology.
It is unique and is ex Lefferts (S.H. & H. Chapman 7/1881 lot 723), Britton (G. Cogan 1/1883 lot 405), Garrett-JHU, Bowers and Ruddy 3/80 (Garrett II), Heritage 1/19 FUN - PCGS64RB.
Photo courtesy of Heritage.