The 3G Model is the new model. The older models are 2G. There's so little that uses 2G anymore, no reason for the wireless providers to continue to keep it running.
I'd worry about it when it stops working and not one day before...
M&P-10+AAC Cyclone - Kel-Tec RFB+Griffin Sportsman Ultra Light 300
ATN OTS 336-70mm 60hz Thermal Monocular
ATN OTS 336-30mm 9hz Thermal Monocular
ATN NVM14 NV Monocular