Yes I did disconnect the battery first as a precaution. When I removed the airbag I did not disconnect the wiring. I simply held it aside as a tightened up the screws. Also, I extended the steering column as far out as possible and diconnected the battery afterwards. I then turned the wheel so the screws holding the airbag from the rear are down towards the floor. This gives you more clearance to use a torx screw driver. You can turn the steering wheel the other way with the engine off to get to the other screw.
Hope this helps.