Just purchased a 4013 non-TSW - Former Colorado State Patrol evaluation gun dated by SW as 1999. Its single stack magazines appear to be unique in my limited experience in that the red follower is flat, unlike my 4013TSW which has a contour.
The only other flat followers I have seen were a 1076 a 39-2 and a 439). I realize the 4013 is single stack while most of my other pistols including the 4013TSW are double stack - so is the flat follower common on single stack.
Also - both factory magazines are stamped ES1 vertically down the front. I have never seen or at least never noticed such markings - wondering their significance.
The only other flat followers I have seen were a 1076 a 39-2 and a 439). I realize the 4013 is single stack while most of my other pistols including the 4013TSW are double stack - so is the flat follower common on single stack.
Also - both factory magazines are stamped ES1 vertically down the front. I have never seen or at least never noticed such markings - wondering their significance.
