Listen to this short audio file and tell me if this guitar sounds out of phase:
While I don’t personally hear anything horrendously bad with this recording, what I do hear is frequency issues caused by some of the open strings within the chords. There are some tricky unison notes abound so a little well-placed EQ might be the better option than fretting about possible phase issues.
** Update **
Here’s a shorter section of the piece where I hear what sounds like a didgeridoo, specifically in the second measure around and on the up-stroke: