For what it's worth, I remember them playing on SNL with a Marshall combo. You could probably youtube that video and see how it sounds live. I want to say it might have been one of the purple tolex anniversary amps with the million knobs and channels, but my memory could be off. Those things could get pretty saturated on some of the heavier modes, it would make sense to me if that's what they used in the studio.
Thanks for that info!