Welcome to Android Central! 802.11b/g/n refers to the wireless protocol, not the frequency that is used. The 2014 Moto G should be capable of seeing 2.4 and 5 GHz signals. Are you saying that your 2014 Moto G doesn't see the 5 GHz wifi signal from your router? On your Moto G, go to Settings>Wi-fi, tap Menu, then Advanced, and then look for an option for "Wi-fi frequency band." Make sure it's set to Automatic.