I think it is more of a perception thing than a physical thing. Not being left handed this is just conjecture but I would think it is like in Hockey you can be right handed and still shoot from the left side just because "it feels natural for you to do that". To switch feels really wierd. It may be that his mind can't get past that nagging feeling that the gun is on the wrong side.
Unfortunately it would mean remodeling all the legends to have a second one with the gin on the left side. Probably not gonna happen. So at this point you will need to train your brain to ignore that.