They’re installed by Spirit who manufacture the airframes, which are then shipped to Seattle for assembly with the wings. No-one will have removed those bolts since manufacture. There no need to touch those bolts for the mechanics to open the door, so the airline opening it to install the WiFi seems like a red herring.
If it’s not in the MEL or CDL then you can’t fly without it. They’re basically a book of approvals for how long you can get away with stuff.
Btw If the tray table can’t be stowed, you can’t take off with anyone in that row because of the danger in an emergency landing.