The serial port pins (rather, square pads on the pcb edge) are visible when you take off the sim tray. GND and TX, the only pins you need when logging messages are the 2 rightmost pads nearer to edge. The RX pin which you only need if you want to type commands to the console is further inside the device, behind the TX pin.

There are schematics on the net, showing the pins, but now I am in a meeting so I cannot dig out them for you.