We bought a remanufactured 350B2 from Eurocopter some time back. If I recall correctly it had used 0 TSO servos, a used T/R drive shaft, a used battery and some used 0 TSO instruments
Sometimes the problem is component supply from subcontractors with long lead times if a component is out of stock , as long as the seller informs the buyer and appropriate discounts are made I don't see anything wrong with it as in the case quoted above.
Disagree that they put a used battery in it though, that's a bit much