Call the NEX customer service line at (800) 368-4088 and impersonate your son. You'll need his name, social security number (which is also his military ID number), and date of birth. The NFO gold wings are sold at the Pensacola NEX as a jewelry item and they are also sold online by the NEX in their online catalog. The reason I'd suggest calling the customer service directly is because locating the item you want online will exasperate your patience, as their website is somewhat painful to navigate without their help. They will also provide the telephone number to the Pensacola NEX and you can choose whether to order them online or from the base store.
P.S. If you wouldn't mind they also sell NFO rings made of gold, I'd like one since the family accountant/boss has long forbode me from buying one.