Well it seems the worst that will happen will be the LED will get burned out. Thanks for the tips all. Will let you know how it goes.
The following website says that at least for hard disk LEDs on normal PC motherboards, the voltage on the LED header is of no consequence as the motherboard will limit the current. The voltage would vary depending on if you had a higher voltage blue LED or lower voltage red LED:
http://case-mods.linear1.org/hdd-header-hints/