Well kind of. I bought a 50 pack of Warm white LED's and the input voltage range was from 3.2 to 3.8 volts with an amperage draw of 20 to 30mA. Using a simple LED resistance calculator, I picked a 3.5 volts as safe average input voltage to the LED, and picked 6.0 volts as the supply voltage. I then entered my desired mA rating and the calculator selects the closest size of resistor needed to deliver the proper voltage & amperage to your led.
This is the calculator that I used: http://ledcalc.com/