I would think many of metallicas tracks were cut with LPs and Strats or some of the hundreds of other guitars they collectively own. I know they use EMGs live but in the studio I am sure they use everything they can.
Just wanted to add, I am in no way bashing EMG as I have had them in some of...
Just my .02...Be sure to gut all the electronics and start new. I just did this last weekend with some help from a forum member and it made a world of difference on my strat. Now I feel comfortable gutting any of my guitars or swapping electronics.
I am into my parts-o-caster for around 450 bucks and it plays better than most new start I have played. Maybe I just got lucky with nice fitting parts...I say try it if you can find good pieces for low prices.