Do manufacturers use 2K primer

So I am finishing up the major panel repair on the 03 Avalanche, get to a 4x2 inch area above the tires, on the flare in the sheet metal where all the paint is lifting. Get out the DA with 80 grit since this metal is so thin to begin with anyway, sand the panel, the paint falls off, go thru what looks like gray 2K, down to bare metal, and the only rust I see are two tiny specs, head of the point of a nail spec is all that I see, nothing rusted thru, just two specs.

Does the gray 2K show me that someone did some repair on this once and it was more poor adhesion to bare metal more than a real problem that should have me sanding more of these arches over the tires? I am sure the specs would seal in epoxy, so maybe just what was skipped during a repair? All of them have something, some bigger, but the worst looking area just had the two specs.
 
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