Nah, it was just a big soap opera, not that big a deal. Mustaine did write an album and a half to get Metallica started, so he was a bit jealous of their success... but it means nothing, was just the magazine culture of the time. Metallica also got into a war of the words with Slayer, and Slayer with Sepultura. It's like WWF(or E if you are gen Y!) trash talk... almost scripted.