Hey man, thnx for your comment.
I'm not really sure if Shavo plays this part (I'm 90% sure that he doesn't), however these exact notes, in that frequency are been played in the cd... They're either played by a C-G-C-F-A-D tuned guitar where the first C note you hear is an open C, or by the bass where if the bass is C-G-C-F tuned the first C note you hear is the 5th fret of the G (detuned) string and if the bass is E-A-D-G tuned, it's the 3rd note on the A string. Anyways, it's the same frequencies. However, I have seen Shavo not playing a thing in the intro in some lives, so I think that it's a guitar. Nonetheless, I like playing that riff, so I do it :)