I would have replaced the oil pump.
As already said the scoring is caused by debris passing through the pump.
The debris is usually from when the engine was build, oil ways not clean enough, oil coolers reused etc.
If the sump is off I would check the big end bearings, main bearings and cam shaft journals.
If you are going to use that oil pump push the middle shaft out of the inner rotor and have the pair surface ground and then machine the aluminium housing to restore the correct end clearance.
Either way good luck with that oil pump.

Steve