I don't think so? Or at least not from any time we're used to. Kaidan and I have tried to work it out and mostly we just went with "earth-enough". People come from all different places. Not just different planets but different universes and worlds.
We've been here a while and somehow trouble hasn't really found us in particular. We can fix the shotgun, and the teeth aren't so bad. Mostly they stick to their side of the fence unless you go out where they are.