I never heard twelve actual guitar tracks (meaning James played the same part twelve times and over dubbed each track on top of one another), on the classic album behind the scenes thing, James talks about how he layered three guitar tracks for the heavy rhythm, left, right, and the thickener. Now, when he recorded those parts, he was played out of multiple amps and cabs, but there's a big difference. There could have easily been 4 mics on 4 different cabs grabbing sound, then being comped into one track on the board, thus creating the "left" guitar part. If James then did that same thing for the right, and the thickener, that would totally 12 mic inputs I guess, but once again, that's different.