I strongly suspect the officer called in the tags before approaching the driver, then asked him for ID, as he should for any stop, for a driver of any race.
He therefore knew the car was registered to the driver and had no reason to ask him if it was stolen.
A very large percentage of cops who are murdered in the line of duty die in routine traffic stops.
This wasn’t a traffic stop, though. Not sure whether the officer would call in the tags before rendering assistance to a stranded driver, or would check the driver’s ID. The one time an officer assisted me on the side of a highway, he did not check my ID; I obviously have no idea whether he ran my plates, though I suspect he did not, given that he pulled over and got out of his vehicle as soon as I flagged him down.