Yeah, it does sound like it.
I always figured he just said "MA...ma!" the way he does instead of a calmer "mama mia" in favor of it sounding a bit more natural, surprised, and genuine... you know, a little less scripted. I mean, if you're driving your car, and a huge turtle shell flies up and makes your car do a front flip, you'd probably be silent then be like "um.... [wtd]>????? WHAT HAPPENED?" rather than "oh dear, I've been hit" the split second you notice the shell hit you.