You have a fee choices. If your faucet was made in 05 and they made another one just like it in 09, you still need to choose the cartridge that was sold to fit the older unit. Which ever one that is. The change although may still make the faucet look the same, can be minor changes such as dimensions within the barrel of the faucet itself. Meaning one part may not fit correctly while one other will.
If both are listed to fix your faucet, then use the newest cartridge that they offer. Most likely its an improvement over the older version. Perhaps in response to the older replacement having issues with longevity?
But if your not sure of your exact faucet ID number and each one uses one cartridge only you need to ID your faucet better then you have. Perhaps you need to take a photo of it and then bring it to the supply place so they can ID it for you. Also many times the part that requires replacement has ID number imprinted on it for choosing proper replacement part. Have you removed it yet? Doing so can help you figure out exactly what part you need to have would be.
Call the Moen parts number hotline. They can assist you in this choice.
Call 1-800-BUY-MOEN (1-800-289-6636)
Or simply visit their parts web site at http://www.moen.com/