I have a Winchester that has been family owned since the fifties. It has looked like this my whole life (53 years) and the sites are not typical like you would see on other m1s. Could these be altered or added?
Yes, your sights have been altered/replaced. The stake mark on the receiver tells me that it had, at one time, an adjustable rear sight. The barrel looks like it still has the original USGI finish. As long as the barrel and receiver themselves are not altered you can easily replace them with standard USGI sights, if you wish.
BTW, that's a beautiful pot belly stock. I like the tiger striping.
Foot I think your grandfather did a great job. He probably was used to the v type sight. If it shoots good and you are going to keep it. He put his mark on it for you to remember. SM PS- Jack is right, it is a real nice looking rifle.