Not necessarily, I have heard that in hardwoods, the top side develops tension wood, which is stronger, and the bottom develops compression wood, in hardwoods the compression wood is supposed to take more set or be less elastic or something like that. in softwoods, the compression wood is supposed to be superior to the tension wood. If I cut a branch that was splitable into several bows, I wouldn't waste the compression/tension wood, I would still try to make a bow out of it and in all honesty I would probably still succeed as I dont think there is a massive difference between tension and compression wood. But those are just my thoughts, others may vary.