According to thrill-data.com, RotR ILL sold old before park opening only twice in the last 30 days.
And RotR didn't sell out until after 11:00 am on 16 of those 30 days.
Of course, the past 30 days are traditionally the lowest-crowd time of the year, so early December won't be quite this good, so you'll want to check out the data closer to your trip.