A wise engineer rebuilds the oil-pump as a matter of course when carrying out an engine overhaul. It has a tough time and wears with constant full velocity operation. Is it worth taking the risk reusing old, possibly worn components?
The more components in the assembly that are replaced with new, the less anxiety the owner will feel, having the full knowledge that every part in the assembly is as good as it can be; the parts listed below may be of interest: