I have a 2007 ML350 so will assume it's close. The Aux jack in the glovebox will read media files only and you have to control all functions from your device. It will not hook up your phone.
I don't know what you are referring to on the cell phone puck. My Bluetooth is in the center console and is removable and from Mercedes. I don't know if you can use an aftermarket model or hook another device into it but it would be interesting to find out. I use an android phone and lately the address book will not show up in the command display, I believe the updates surpassed the benz and since Mercedes does no updates on any of the computers I believe I will have to buy a new one to get the features back.
The later years models have bluetooth built in and they have USB ports, which will allow user function, still don't know if your phone would work through it?