There cannot be, because we're all different. I have little doubt that most folks, given enough time and repetitions, could learn to shoot as well from their non-dominant side... as evidenced by your friend.
But given the time limitations in your basic class (even a week-long one), and the fact that those same most folks are NOT going to religiously continue to hone those off-side skills once they leave... well, looks to me like a collossal recipe for disaster.
Just sayin'...
.