I just got a SA M1 Garand from CMP. I'm not sure how to decode the serial #'s on the various assemblies, but I think it may be from the early to mid '50's. The weird thing is, (IMO) the stock has no serial # stamped on it. It has the SA cartouche and the Circle P cartouche, but no #. I am 100% sure this stock is completely untouched and original. Why no # on the stock?