Where the bolt release is at was replaced by a small flat piece of steel that folds over to take the bolt out. The scope mounts on top of the flat piece of steel with two screw holes. Very similar to the Wincesterside mount scope mount. I assumed this was done by RR-it looks time period like??? It is held in place by a set screw. It may be a Remington, I am not sure. It is marked as a refurb in 1944 at Rock River Arsenal. I would have to check for the other markings. I will get it out one day a post a picture. The rifle is in my vault. I am pretty sure it is an 03A3-but I could be mistaken, I am not an expert on such things. Tom.