Thinkpads Forum

http://forum.thinkpads.com/viewtopic.ph ... 4&start=30

As posted towards the end, we know that 802.11N systems without WWAN have 3 antennae, but it was speculated that those with WWAN have 2 antennae going to the WiFi, and 2 going to the WWAN..but no one has been able to confirm on this configuration.

If anyone has a setup that has 802.11N & WWAN can pop the keyboard off and check, we'd be greatly appreciative.

No speculation -- it is as you state.
Additional clarification: the 3rd N-card antenna is not standard even if one does not have WWAN, i.e., no WAN and non-N WLAN card means only 2 WLAN antennas are built-in. The machine must have been ordered with N and without WWAN to have the 3rd WLAN antenna.