"Absolutely!, in fact many of my students say the 'mirror image' effect actually helps them. More significantly, teaching guitar isn't much about the student copying the teacher's finger movements at all and much more about explaining concepts and theory, problem solving, inspiring with fresh ideas and insights and then demonstrating those things to the student to hear it in action. Any specifics to be physically played and practiced by the student are always written out with the fingering depicted very clearly where neccessary. There's no disadvantage whatsoever, in fact it has proven to be beneficial".