Looks like those are the surfaces that are hidden when the cutters are closed. I imagine that depending on how tightly the parts fit, they might not even be able to take the factory paint/coating because there's no room. I wouldn't worry about it.
Edit: I have 3 NWS pliers with the same black coating, 2 look perfect and 1 looks like it was dunked in paint, has runs everywhere and is ugly. But it still works great.