External GSM Antenna
The GSM-connector to be found near one of the screws (see Disassembling Neo 1973 in wiki) is:
MURATA MM8430-2610RB3 SMD RF TEST PORT
For a nice fitting adapter search in Google for MXHS83QE3000
There is no hole for the antenna in the back of the case but you can make one easily with a soldering iron or a drill.