Pretty interesting find. These guys must've been some of the earliest US Marxists. Marx had an early influence on a US labor organizer named William Sylvis in the late 1860s and moved the headquarters of the First International to the US from 1872 to 1876.
Yes it is. The labor movement had many interesting beginnings. What I find the most intriguing is that it had different outcomes in the US as it did in Europe. European socialists saw the union movement as a class struggle. In the US, however, it was actually an effort by workers to acquire fair wages and working conditions and not a "class struggle". The great filter of American opportunity affords every man the dream that he to, may become rich. In Europe, the "dream" was to destroy the rich. America may have been founded by Northern Europeans, but there the similarity ends. America is a unique culture and society distinct from its European ancestry. The election cry of "Red Staters", that we don't care what Europe thinks, is a demonstration of that essential difference.