I just compared Best Friend from both copies. On the original copy the song begins as mono, as one of the tapes is being flipped. At :03, one of the sources kicks back in and it's a sudden edit in the right channel. On the bootleg this has been smoothed out, as there is a fade in back into stereo a couple seconds later. Perhaps there are other tape flips that have similar treatment.
They've also EQ'd it to add a bit more top end.
So sure, it's different and worth a listen, but it's not a "newly found tape" as it was marketed to be.