Somebody went out and bought themselves a really nice looking aftermarket stock. Probably from Richards Microfit by the looks of it. (They are a pretty good outfit by the way based on my experience with them)
Now granted this is a Low Number Rifle. But from what I have heard from various folks. They are usually safe to shoot. Unlike some of the ones made by Springfield under the million Number serial numbers mark.
Anyways with a little more work. You could wind up with a rifle that cam match the quality of say a high end Model 70 Winchester or a Remington 700. But that is cheaper than them if you watch your pennies & have an honest Gunsmith.
Which Thankfully most of which are!