I have seen that on a couple doors I have. I think the metal wears and cracks as the doors get opened and closed, and the body flexes.
I think you should be fine welding them up, but I have never done it.
You could pull the skin off, but that would be a hell of a job. I would rather find better doors than do that.
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Pete
'72 K5 Blazer
'87 V10 Suburban
Pictures of my trucks!
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