Scored Main Cap Bearing - Ouch

Someone didn't chamfer the oil hole either before or after the crank was ground. That's what did the most damage. Then the junk came from that.

Look at all the mains and I bet you find the same thing.

Also, there is some water patterns on the bearing. If they didn't line hone it, they should have. None of them are ever straight, round or sized the same after years of use.