I don't see any reason why it would be bad in the first place. As long as some oil or assembly lube was trapped in the timing cover when the cover was left sitting.
If your still concerned (or if the parts were left-over from a previous build or failure) you may remove the timing cover, then remove the oil pump cover and examine the inner and outer rotor.
If you don't see any evidence of scoring, pitting etc.. check all of the tolerances. You should also remove the relief valve plug and inspect the relief valve as well.
You can purchase the pump rotor set and small pump cover separately.
If these parts were from a previous engine failure, I suggest to replace the old oil cooler; they are not expensive and flushing old oil coolers is NOT a good practice.
Good Luck!