kinda like who came first, the chicken or the egg. Wondered which came first the Walnut or the Birch. Also through all the stocks that I've seen, I noticed that the majority of walnut stocks have the DOD and proof stamps, but the birch only about 15-20% have the stamps. Also, the difference in grip size. Most birch have a larger grip size than walnut. I've seen a bunch of the larger grip size in walnut also, but it's not the norm. Are the different sized grips something that was planned or something that was significant to the manufacturer? Thanks Bill!