Yes, it will take time for the flight to post (usually it happens overnight, but sometimes it can take a couple of days), and then it will take a few more days for the status to trickle through the system including existing reservations.

When your return posts, you should get the 100% bonus mileage for 1P, but you won't be able to get the new status in time to help your upgrade priority on the way back. Maybe you can ask the GA with a printout of your current EQM and the stub for your outbound (to show that it would push you over the 1P threshold), but I doubt it will do you any good.