Since the limbs of self-bows, unlike laminated bows, will tend to take on a bend over time, it may not be the end of the world if one limb is curved slightly more than the other. It would be more of a problem if the limb were torqued or twisted. The best thing is to see if a bare shaft can be tuned to fly well out of the bow. If so, then you have an interesting bow that shoots fine. If not, then it may be possible for a bowyer to correct the tiller by judiciously sanding down or otherwise removing some wood from the offending limb. Or, you could trade it for something else....