If their entry requirements are AAB, I think they will give you an offer of AAB (or possibly below) regardless of your predicted grades - they are very unlikely to raise their entry requirements if that's what you're asking.
And yes, it's possible (and not very rare at all) to get an offer if your predicted grades are lower than the entry requirements, although they'll most likely just give you the standard offer, rather than lowering it to match your predictions.