Yes, thats true for a Diode, but not a Light Emitting one.Backwords or fowards an LED will not work the same
LED = Light Emiting Diode.
Diode = Allows electricity to flow only one way
i played around with a lota things in the past, and im pritty shur if you take a LED and connect it to a power source it will work no matter witch way u put it. you can test this just by reversing you HDD LED or one of the others and see what happens. if your too lazy to do this, and you dont beleive me, i will do it if nesessary.