October is also a very popular convention month at WDW. This is what first actually changed October from value to regular season. And, now it is getting more popular to go to the parks during this time. We went the 2nd week of Oct. last year and find it busier than when we went the 2nd week of December.
But as some of the other posters mentioned discount codes probably aren't available yet anyway (other than AP's). I believe the discount codes are determined after they find out the amount of vacancies that are available. (usually anywhere from 1-5 months ahead).
My recommendation is if there is a specific time that you want to go, make the reservation because it can always be modified if the price goes down (or you can even change to another resort), but if you don't make that reservation and you miss that discount window you may not be able to get in there at all. Some resorts only open a small amount of discounted rooms depending on availability (they can book up a resort on a discount code the same day it comes out).
