Depends on how "rebuilt" you plan to go whether it's necessary or not.

Proper machine shop build with all clearances checked and corrected to stock non race specs, not necessary.

Old school loose race clearances or just a backyard hone, re-ring with new rod and main bearings on a 100,000 mile core, probably not a bad idea.

Will it hurt anything? Not likely.

Make sure you disassemble it completely and clean it. Countless examples of machining debris left in them from manufacture causing the rotors to jam and shear off the pump drive, making engine go boom.

Kevin