Yea those bearings look pretty shitty, enough to where anyone would advise you to micropolish the crank shaft journals. There should be some marking indications on the bottom of the block indicating which size main bearings it uses. grade\size 1,2,3,4. On the KA its on the oil pan gasket surface. It will be stamped into the block someplace. Rod bearings are a little more tricky. nissan bearings are numberd to tell you the thickness. along with GM.
When its all said and done and you have the new bearings use some plastigauge as secondary insurace to double check the oil clearance.
Have someone give you a hand figuring out what bearings to purchase. NUMBER EVERYTHING.!!!! Pistons are directional, rods are directional, rod caps are directional. Do not mis match rod caps with different rods. Make sure the pistons that came out of that cylinder go back into that cylinder so your cylinder to wall clearances are correct.
There should never be any metal to metal contact on bearing surfaces. But you defiantly had metal to metal contact.
If you can take your finger nail and feel grooves on the crank journals that is a definite sign that your crankshaft is scared. It will have to be ground undersized and used oversize bearings. Not good for making power....... factory rebuild and a little more boost then okay........ If your gonna put a mans turbo on it, its life expectancy will be questionable.
fsm will have the locations of where the bearing sizes are stamped. main and rod