Could easily be original.
My old engine only recently came out, had never been apart or out in it's life. Not even a head gasket. I've raced the shit out of it for the last 3 years, someone else did before me, and who knows what it did before that since 1989....
Engine still had bore hone marks. Only thing that killed it was a big end failure..... I did a session of 30+ flat out laps in a Qld summer dicing with Group A cars, without an oil cooler. No doubt in my mind the oil would have been so thin it simply lost it's ability to lube.