U.S. "Trade Dollars" Made in 1949
In 1949, the United States desired to send silver trade coins to Chiang Kai-Shek and the Republic of China. New dies for an 1898-dated Mexico City Mint (Mo mintmark), assayers initials AM, one-peso silver "dollar" were created. These differed from originals made in Mexico in 1898 in that originals had 139 beads around the reverse border, while restrikes had 134. The San Francisco Mint restruck 2,000,000 1898-dated Mexican one-peso coins, and the Mexico City Mint restruck 8,250,000 similar pieces.
Thus, in 1949 the San Francisco Mint produced 2,000,000 silver "trade dollars."
The Trade Dollar Remonetized (1965)
A little known fact is that the Coinage Act of July 23, 1965, which provided for the production of clad coins, contained this wording (Section 102; italics ours): "All coins and currencies of the United States (including Federal Reserve notes and circulating notes of Federal Reserve banks and national banking associations), regardless of when coined or issued, shall be legal tender for all debts, public and private, public charges, taxes, duties, and dues."
Under this act, it seems that trade dollars were given the legal tender status that had been taken away in 1876, although probably no one in Congress was aware of the implication! Similarly, as the 1884 and 1885 trade dollars are now legal tender as are, it would seem, all pattern coins.