On an original .22 stock, there is a small notch cut out of the forward end of the magazine opening, to clear the .22 magazine. Your rifle looks really nice. I would have no trouble justifying the use of a Dremel tool to make the notch for the cut off lever. Does the number on the bolt match the receiver? I notice the J5 bolt code. This is a common code for national match rifles, later than when NS codes were the usual. My original made in 1929 Springfield Sporter has a matching bolt with a N. S. Mark.