It's not really worth it to prove to them to give you a brand new hard drive. Apple Hard Drive as a matter of fact it's slower then today Seagate. Apple Hard Drive speed are only average. Unless your is 500GB+ it's a lot better to backup all your data and buy a newer and bigger Hard Drive that is faster then Apple. Newegg 320GB Seagate is less then $100 and is faster then Apple one.
They don't replace it with a hard drive from 3 years ago. In several AppleCare cases, I've had current-ish parts put into really old systems (yay for 3 year AppleCare!)