Can a 120 Aerohive AP be used as a wireless bridge to bring wired LAN to another building that is within range?
Absolutely! Any two Aerohive APs can be used to bridge wired networks. Depending on where you are installing the APs, you might want to use a 170 to install outdoors and remove obstructions (such as glass with a reflective metal coating), or a 350 for maximum 3-stream radio performance.
You may also want to look into directional antennas depending on the distance needed to be traversed. Mount the AP inside and only penetrate the building to get the coax out to the antennas. There is some lightning protection that needs to be done also. We use 340's to bridge between 2 building that are well over 100m apart with great signal strength.