Hello Christine,
How exciting that you will be spending the holidays at Walt Disney World. The spirit of the season is extra magical in the parks and I am sure you are getting really excited to go during that special time.
On a recent visit to Magic Kingdom, I do not recollect seeing any commemorative anniversary "it's a small world" merchandise. However, that is not to say that it doesn't exist. I did find an adult t-shirt for the anniversary of the attraction in both parks at
DisneyStore.com by searching "it's a small world". It is limited release, so keep in mind that quantities are limited. I also know there is now a special Dooney and Bourke "it's a small world" collection of bags and purses, but I don't believe the design includes the anniversary dates. Another suggestion would be to download the
Shop Disney Parks app. Lastly, keep a regular eye on the
Disney Parks Blog, as new merchandise previews are often announced there.
Good Luck in your hunt! Have a magical trip.
~Allison L