This is a complete reverse die trial, struck in zinc? It is misdescribed in Pollock. For more on this, go to P3085.
It is believed unique and was first seen in Stacks 6/88 sale from which the image above was taken.
2 additional examples in copper and brass were part of lot 2368 in Ira & Larry Goldberg Coins & Collectibles 6/04 sale.
The brass example is shown below.
Note: The genuineness of these pieces have been questioned so they were not assigned numbers in the new Judd book pending further analysis.