No, that "ping" you guys were talking about definitely came from the bass, in the opening. The guitar joins in later. Guitar World's songs are generally wrong in a couple places every time, but "Dig" wasn't even close.
The opening note is a B, btw, not a C#. And the popped notes are G and C#. It's not a tritone.
On the CD, there a couple songs where he tuned BEADG, according to my ears. Dig, and Death Blooms, and a couple others. Live, he plays them in his usual tuning, GCGCF, by transposing the song up a half step, so it sounds a little different live.
I, for one, will likely never tune differently. Standard for me!