The motor is screwed into the faceplate, and then the faceplate screws into the gearbox. Although, I would look to not rely on it inside a competitive robot as it may break/pull out
Oh yeah, never rely on it being solid in the past as the screw mounts can crack/split/shear etc but it's nice just to be able to sit a motor/gearbox down on the workbench and not have to worry about keeping them together