That bit of slag in photo 2 might impede the cyclonic efficiency of the fluid. So I'd clean up the bit of slag in photo #2 a bit with a die grinder. I'd completely ignore the filled/unfilled machined surface blemish in photo #1 because it doesn't reach to the important inside edge of the impeller's mating surface which isn't a close tolerance fit to the impeller in any case. Cooled coolant is drawn from the lower radiator hose port and pulled forcefully through the large round hole in the center of the housing, then is thrown out forcefully by the impeller to the round ports in the housing. I'd be more concerned with any casting defect that blocks the inlet pathway, as the suction side of a centrifugal pump is the most limiting flow factor. You have provided no photos of that passageway. It's a shame that such poor quality high $$ aftermarket parts are shipped in the first place, but on the other hand a lot of the original cast iron parts have similar/worse defects that no inspector even looked at much less attempted to fill. Yet they worked just fine then and now.