If the light's now off after being reset, do nothing. It's possible that someone had the airbag disconnected for some reason and turned the ignition on setting that code.
To diagnose a contact reel vs airbag (if a "permanent fault"), one removes the airbag and temporarilly installs a test resistor (special tool) and then turns the steering wheel back and forth from lock to lock. One cannot check airbag resistance as that'll blow the bag.
I've seen where contact reel housings are badly cracked from age and then might become a problem but in your case, if the light's now off.....drive the car for a while and if the code (light) doesn't return, forget about it.