I can only speak for EK, where a lot of F/Os have no previous command time and still pass the upgrade with no problems. The only requirements are seniority, minimum of three years in the company and, for the 380, 2,500 hrs on type. EK is so short of Captains on th e big bus I can see the 2,500 requirement changing before long. Do bear in mind that there is no recogniseable employment law here so the requirements can change on a whim.