It definitely is still worth applying for, yes! They may have given some out some AC invitations already - but there will still be plenty left. Rolling firms accept that a huge number of applications tend to come in the final days of the application process - so there will be plenty of invitations left which, even those who applied near the deadline, could be given one. From my understanding a lot of their core decisions will be made around the week commencing the 3rd of January - so even applying by the deadline still gives you a chance to get into an AC. So go for it if you're interested in CMS!