I believe it does. As (to my knowledge) the carriers don't modify its software at all I can't see any reason why they'd need to approve an OS update. I suppose we'll see when the next one is released.
Mobilicity claims they're locked, but they also claimed that about the Sony Ericsson TM506, which wasn't locked. I have yet to hear from someone who actually bought it.
I can certainly see some outraged buyers if it does require carrier approval, particularly if carriers disable some popular features.