Hi temartemm,
There could be a number of different reasons for why appointment dates for the At-home GMAT have not opened yet for the last couple of weeks of the year. It's possible that those dates have not been 'staffed' yet (the At-home GMAT requires that a live person 'moderate' your Exam and pay attention to your camera and microphone feeds - so a certain number of those Moderators have to be available to staff the Exams and it's possible that those employees have not been booked yet). That time of year also includes a number of Holidays and some Businesses won't operate on a Holiday.
It's reasonable to assume that Test appointments will open up at some point for those dates, but since we're approximately 2 months away from that timeframe, if your plans are all based on taking the At-home GMAT sometime at the end of the year, then you have some time to adjust those plans.
GMAT assassins aren't born, they're made,
Rich