I have a 1943 DUO 98K that is all amtching except I can not find any waffenampts or serial numbers on the stock. The Collector Grade book on the 98k Says there should only be a SN on the bottom of the stock but none on the 1944 DUO. Any one know if there is any markings inside the stock so I can determine if this is the original stock. I have owned this 98K for over 40 years. Ant info greatly appreciated.