Not exactly. There is a trick called "walking the reservation." Officially you can call 11 months from date of arrival and reserve 7 nights. What some have done is call earlier and start a reservation and then change it daily until they get days they want. Example: suppose you wanted Dec 25 to Jan 1; the 11 month date for calling is Jan 25. What some are doing is calling Jan 19 and reserving Dec 19 through 26 and thus they get night of Dec 25. On Jan 20, they call and cancel the 19th while adding the the night of the 26th, on Jan 21 they call and cancel the 20th and add the night of the 27th, etc. on a daily basis until they have their Dec 25 to Jan 1 vacation time.
Is "walking" needed? Highly unlikely for just about anything anytime of year. The exception however could be for particular rooms in low numbers during the Christmas season such as GVs or AKV concierge; another possible time to consider it is for a BLT GV MK view when you want July 4.