I seem to remember reading something about some walnut stocks being used later but I don't remember where and I can't find anything on them now. The stock will most likely be dated 1943 as that's when it was made but the serial would not be applied until it was matched to a rifle so it should match. Good luck. I haven't seen many mismatched K31icon's but as the numbers of available rifles get smaller, they seem to be turning up now.