This copper pattern is considered a transitional design between the 1792 half disme J7/P7 and the regular issue.
This pattern uses the flowing hair design without stars similar to the 1794 pattern dollar J18/P27 combined with a reverse that still has the denomination "half disme" on it. This makes me believe that this pattern was struck prior to the copper dollar trial. This was replaced with a wreath on the regular production issue half dimes.
The pattern is unique with the only known piece being in the Smithsonian.
Photo courtesy of the National Numismatic Collection of the Smithsonian Institution.