Advice on skin fitting (metallurgical)

They look absolutely fine. When they de-zincify the pink stuff is soft, almost crumbly, and very obvious. Give them a tap with a hammer inside the boat just to be sure there's nothing hidden.
 
It looks OK to me too

It does not look as though the pitting has any significant depth

If the pink colouration is only the surface there is no problem.
 
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