Ah, no. It is an option that wasnt available on the 08 (at least not in CA..). The phone button (on the Shaker 500/1000 systems) will mute the radio in the event you have a phone call.
You can get an after market system installed for 400 or so. I bougt my system for 420 and did the install myself. A note on that...the mute isnt a full mute, so if you like to destroy your eardrums to Metallica / Iron Maiden like I do, make sure you know the bass will still rumble a bit