No, even if employees doing the same job, function better if there is a hierarchy, even if they have the same title and the same pay, seniority is important to employees and they will revert to it, even if it is not presented by management. You will still have employees saying "I've been here longer than you" or "you have seniority, you decide". There will be a hierarchy weather management approves it or not, so you might as well set it up from the start.