Last year they offered them through Jan 6. We tried to book when we were there that week but they were full (I called only about two weeks in advance though). We're happy to be going Nov 22 and have a tour booked!
I got our tour booked for Dec 13 at 2pm this morning, called about 7:55am PST and was on hold for 15 mins. The CM said we would go on IASWH, HMH, and Jingle Cruise. She said she got to do a preview yesterday as the guides were training and it was great this year as they combined lots of the holiday info with 60th facts. Can't wait to experience it this year!