Well for starters how sporterized is it? If the original stock was cut-down and it has the original barrel a military stock will fit it but the hand-guards might not if they are not for your model. The 1903 had the rear sights on the barrel ala.mauser and the 03-A3 had them on rear of the action, locked to a dove-tail. But this is if you want to restore it to original condition. I also know where I can lay my hands on a nylon parade/drill stock for the ,03 if you want a original synthetic one.