Typically, nonrevs are cleared at either the 1 hour, 45 minute, or 30 minute mark before scheduled departure. However, if the flight is wide open, if there are no weight restriction issues, and if airport operations determines early-on that all standbys (revenue and non-revenue) can be accommodated, then it's possible to be cleared at check-in. If you are eligible for upgrade, then you will get a confirmed economy seat assignment to get you through immigration, and be placed on the upgrade waitlist for clearance at the gate. Good luck.