BGW320 Wifi chipset removal

To do so would be to run afoul of 

If the AT&T Equipment was damaged due to your intentional acts, negligence, or use inconsistent with this Agreement, as determined by AT&T, you will be responsible for the price of repair or replacement. Any tampering with the AT&T Equipment, including, for example, opening and attempting to modify the Equipment will be treated as damage due to your intentional acts or negligence. You agree that you will use the equipment only for its intended use and not for any other purpose (such as on another AT&T network, or on another provider’s (non-AT&T) network). You agree to use appropriate and reasonable care in using all AT&T Equipment.

You may disable the radios in software.  If the no physical radio is a hard requirement, then the Consumer/Small Business shared fiber service is not for you.  Contact an AT&T Business sales rep about a dedicated fiber offering.