93_SVT_FREAK:
First:
I hope you, your car, and everyone else are okay!
Hi. I just scanned an uploaded the following:
http://www.veryuseful.com/mustang/tech/airBag/images/AirBag92Code31-Page1of2.pdf
http://www.veryuseful.com/mustang/tech/airBag/images/AirBag92Code31-Page2of2.pdf
A few things:
1) No worry at all about a new air bag going off!

NONE! If a sensor was jammed "on", the diag controller would see that, report that, and blow the internal safety fuse after 3 ignition turn ons.
The first/second gen air bag controllers are a dual stage setup. There's a safing sensor that gets activated at ~5mph (head-on crash into brick wall). Then, the main sensors get activated at ~15mph (head-on crash into brick wall). So, if any sensor is "stuck on", that's easy to detect, and the diag control blows the internal safing fuse.
2) My
guess is that you see the error because of the activated air bag. That's easy to check! Just remove/disconnect the air bag and see if the code changes to a code 34.
**NOTE TO OTHERS: Since his air bag has deployed, he does not have to disconnect the battery and wait ~1min to perform the above test. But, for non-deployed air bags, you MUST ALWAYS disconnect the battery FIRST, then wait, then remove/disconnect the air bag.
93_SVT_FREAK when you connect your new air bag, then you MUST disconnect the battery, and wait ~1min. No big deal.
BTW: I don't think that the pages I uploaded will be of a lot of help to you since the cause of the error code is likely the deployed air bag . But, they are good reference so that you have a idea of what the error codes means, why you're doing the test I suggested, and what it all means.
However, it is possible that when you do the test, you still get an error 31. In that case, my guess is that the clock spring went because of the current that was used to deploy the air bag. That does happen in some cases. Ford does recommend that the clock spring be replaced after an air bag deployment. But, I don't know if you can even get a new clockspring any more. And, very few small body shops replace the clockspring.
Let me know the result of your testing.
Good Luck!