I asuming that there were two sets of pics, the really prelminary ones , and then the more finalized ones. The fact we saw the more finalized ones first doesn't mean they are older, probably someone came across them first. I think the ones at the Toy Fair were probably the prelimanry ones because if you compare the pictures, you see the TF ones have detail and parts taken away from them ( which were in the more finalized pics ) and that leads to the question , ' Why would TLC take things away from a perfectly good set? ' , so i think that the more finalized ones are more reliable.
Of course i could be completely wrong ( which always happens to me ) , but i just gave you my theory.
EDIT : If you could understand it.
It would be a shame if we had a brick build jet pack, it would be two big and un detailed.