John,
On my COE I tried 3M Window Weld and it holds, sort of. After several months one of the driver's side steps started to separate from the metal base. I used some more of the Window Weld, but I don't think it is the final solution.
Someone should just start over and mold these with a different material so we can bond these to our step plates. You would think Steele Rubber or someone like that could come up with a solution. There is a small shop that makes reproduction rubber for Diamond T as well as Federal trucks. I don't think you would want to use these pads as a basis for molds, given the flaws that they have, as mentioned earlier in this thread. Does someone have NOS or excellent steps to use for a mold?
Kent