Interesting that he quotes something by Murray from his pre-anarchist days to “prove” that Murray himself knew that he wasn’t “really” and anarchist.
Actually, if I recall correctly, Rothbard is said to have first become an anarchist in 1950 and the piece mentioned is said to be “from the 1950’s”, so it’s most likely not from before he became a complete anti-statist. That said, anarchists (like any other normal people) change their minds about stuff all of the time. By, at least, the time of the New Banner interview circa 1970(?) he was using the word anarchist to describe himself, if I recall correctly.
For what it’s worth, the article that Anarcho is citing as his critical source (“Are Libertarians ‘Anarchists’?”) is available online from Mises.org (has been for over a year now), which is almost certainly how he came across it, although, as per the usual AFAQ standards of scholarship when it comes to anarcho-capitalists, he doesn’t link to it. It’s the article in which Rothbard declares himself a “non-archist;” at the time his position was basically what Bob LeFevre was arguing for in the 1960s; that is, he had come out against the monopoly state as such (he explicitly argues against “limited government” in the article, and argues that “the pure libertarian must advocate a society where an individual may voluntarily support none or any police or judicial agency that he deems to be efficient and worthy of his custom”), but chose not to call himself an “Anarchist” because, at the time, he thought that “Anarchism” entailed either coercive collectivization, Proudhonian theories of interest, or Tolstoyan pacifism, all of which he rejected. By 1965 he had changed his mind and was speaking positively of anarchism and anarchists (see for example Liberty and the New Left, from Left and Right 1.2) as examples of libertarian politics, and by 1969 (see for example “Anarcho-Rightism” in Libertarian Forum 1.13) he was definitely using both “anarchism” simpliciter and “anarcho-capitalism” to describe his own views. Of course the big shift had partly to do with the fact that he had broken decisively from the Right and was hanging out with anarchists within the New Left; it also had partly to do with the fact that, based on the textual evidence, he seems to have read a lot more actual anarchist writing in between.
Tucker himself never described himself as a “mutualist.”
I don’t know off the top of my head whether or not Tucker ever specifically used the letters M-U-T-U-A-L-I-S-T as part of a description of his own views, but, just from a quick glance at materials I have on hand for electronic search, I am reminded that Tucker describes the economic principles he subscribes to (specifically, the cost principle and co-operative organization of capital) as “mutualism” and “mutualistic” in Mutualism in the Service of Capital (originally from Liberty, July 16, 1887; reprinted in Instead of a Book).