That's highly doubtful given that the crossover in ideology was very high in the industrial Midwest during the Progressive era.
To quote American Federation of Labor chief, Samuel Gompers, in a speech made in 1905: "If the colored man continues to lend himself to the work of tearing down what the white man has built up, a race hatred worse than any ever known before will result. Caucasian civilization will serve notice that its uplifting process is not to be interfered with in any such way."
This sentiment is repeated many times in Union propaganda and pro-labor speeches. And labor legislation at the time backed this racist agenda by limiting economic opportunities for blacks and other minorities. This is why the northern regions that had the highest union membership also had the largest Klan member roles. There almost certainly was some Klan dislike of those few unions that sought to further the gains of minority workers, but the major unions did not face Klan opposition.
Benjamin
@mowque - Where in central PA are you from? I grew up near Hanover in south central PA, but I went to Penn State and my parents now in Huntingdon county.