Take some shots in better light on a tripod and aim at a certain thing and see if it's on or off and MA from there. I was going to do that on my 70-200 awhile ago but never got around to it and think there's a thread that explains the process a bit better. I'm sure for those particular shots it was the low shutter speed more than the need for MA.
Ninja edit!!!!! haha I found a thread that has links to other places that should get you the answers you need. Good luck and let us know how it turns out.