Sweet tones! I personally love the A more.
Speaking of choosing which one is the real thing... The same as my colleagues above, I think that the second clip sounds more "live", but first of all because it has more gain, which leads to more dirt between the mutes, less punchy low end, and more harmonics. This is the main difference between two clips and in my opinion this difference could be diminished by balancing the gain amounts.
UPD: oh, the B also has some upper midrange harmonic "dirt" or oversaturation, and a tad less 300-400 hz. I remember doing a comparison between AMT P1 and 5150, both into 5150 poweramp. It was the same back then. The real 5150 pre had that dirt and was just a tiny bit thinner. So I believe that B is 5150 pre. It's still not crucial and can be easily matched IMHO.