The windage knob is the "smaller" variety ... I'll bet the SBS matches. The fixed rear sight base is the earlier "stapped" variety and the stock is made for that. A real nice rifle. I highly suggest locating a copy of Springfield Model 1903 Service Rifle; Production and Alterations 1905-1910 by C.S. Ferris and John Beardicon. A little book with a big name that has all the changes in it. It's out of print but fairly easy to locate on the used book market online.