New or a used one can be checked internally by removal of all cover philips head screws and make a first visual check of the gear external circular surfaces and housing common gear surfaces then, shim gauge check 5 places per Nissan service manual (1990) page LC-6 instructions. E-mail me asap if you think that your pump should be good but you will check soon to confirm it is OK
Follow Ups
TT oil pump without internal damages (scratches) - qcsolo09:13:20 08/26/05