Apologies if this has been posted before. I just came across it yesterday, and was fascinated by it.
It seems to be the actual recording. Comparing it with a tab I have from an old Guitar World's Bass Guitar, it matches note for note. You can also hear studio bleed at various points, making me think it's the real deal.
I've seen a few threads about isolated bass tracks, and how the final mix often makes the bass track seem wildly different. Maybe it's just me, but it sounds like Nate Watts was playing a bass with terrible action.