Paquet's trade dollar design without date. This is listed under 1873 as J1320-J1321 in first 7 editions of Judd. The following is excerpted from the May 1999 Bass I sale and is the reason for the 1876 date.
"For many years this coin, which bears no date, was included among patterns of 1873. However, Walter Breen has suggested that this may represent the result of the $600 paid to Anthony C. Paquet for hubs made in May 1876. At that time some thought was given to redesigning the trade dollar, and Paquet, who had been working in the private sector for over a decade, was tapped to do the work on commission".
Additional support for an 1876 date was found by Roger Burdette in the Mint Archives. "Pattern coin dies held by Coiner (Bosbyshell) on Dec 18, 1877: Trade Dollar dies – without date made by Paquet, 1 obverse and 1 reverse."
Examples were struck as follows:
Silver J1320,J1475A/P1627 with the following examples confirmed.
2) Farouk, Vickery-72 ANA, Bass-HWBRF
3) Ewalt-Stacks 11/65, Heritage 2/87, Heritage 4/17 - PCGS62
4) Christensen 9/80, Wyoming collection
5) Harte-B/R 3/81, Fred-B/M 11/95, Heritage 4/17 - NGC66, illustrated above
6) Judd 1st-7th edition plate, possibly one of above
Col Green owned 3 of these according to the Newman inventory.
Copper J1321,J1475B/P1628 with the following confirmed.
1) Farouk, Vickery-72 ANA, Wyoming collection
2) Leidman in 1972, Bass-HWBRF, B/M 5/99, Wyoming collection
3) Hughes 7/80, ANR 9/03 as NGC65RED, Simpson collection - PCGS65RED
4) Harte-B/R 3/81, illustrated below
5) Summit coin 8/92, R. Meek per Pollock
6) Heritage 4/17 - NGC64RB, possibly the same as #4 or #5
Reverse hub trials, struck in white metal, JA1876-3/P3412 are also known.