I'd say that number 11 Wagner in the first picture is the oldest. Notice how in the first picture, the 11 handle is thin up next to the body of the skillet, and that it has the obvious brace running along under the handle going aways back.
As the later skillets were made, they were thicker in the handle up next to the body and therefore the less need for the brace and the reinforced pad, as in the 11. We know that as skillets got newer the pad and reinforcement went away, so I'd say, the reinforced pads were going away, as evidenced by the other two pictures of the skillets, which clearly show less pad.
Those are my thoughts anyway. I am always anxious to hear what others have to say. Besides, if I keep talking about these handles you all are going to start calling me Steve Stephens.
I wish he wouldn't talk about them so much. Everytime I pick up a skillet anymore I look at the handle first. I ain't tellin him though.