Originally Posted by mecabq

Yes, if the registration is open at that time and if you are allowed to go against the grain and walk back airside in T1. (If you try this, please let us know if it works.) But I am not sure the point of using the T1 option -- wouldn't it be faster just to go through immigration in T3, use the desk there (if it's open), and go back through immigration to catch your connection? You should be able to then use the e-gate to leave Dubai if they issue it right away, further saving time.