The earliest production of the Magnum action and the Express models also had the front sling stud attached on the front of the forearm. Everybody decided this was not a good spot for such hard recoiling rifles so the stud was moved to the barrel.
There are also a few 750- (Magnum) and 760- (Express) rifles with the stud on the forearm, but by this time most will have the stud on the barrel.
Chet15