Oil pump.... reuse or buy new?

Those wear and score marks on the insides and outsides of lobes is where a lot of the flow/pressure capacity gets lost. I'd replace that, no question. I know the budget is constrained but, as said, it is good insurance.

Service limits (which tend to be on the sloppy side):
- Pump cover flatness variation: no more than .0015"
- Minimum inner and outer rotor length: .825"
- Minimum outer rotor diameter: 2.469"
- Maximum clearance between outer rotor and body: .012" (but scoring will effect this)
- Maximum clearance between inner and outer rotor lobes: .010"