What is also interesting is how this stacks up with an article I read today on the Krugerrand, being the worlds first legal tender non denominated coin.That was the intent of the trade dollar except they did put a denomination on it.
They did call it a Trade Dollar but it was used in China at the value of its silver content, not directly related to our Dollar.
Welcome to the joys of Bimetallism, the "Crime of 1873," and the Bland-Allison Act. FWIW, the trade dollar regained legal tender status in 1982 to make enforcement of anti-counterfeiting laws easier.
Where is the denomination on a 1794 half dime? Or a 1066 penny of William the Conqueror? The Trade dollar got its legal tender status back under a resolution of the Congress in 1933, and as the law of the land in the coinage act of 1965.
The 1883 No-Cents Nickel is another coin without a denomination. I'll go along with the 1965 date for legal tender status, although the law was amended to clarify what legal tender meant in 1982.