They do sell the lamp in the gift shop. However, Aulani can not sell it to you over the phone and ship it to you. You will need to find a personal shopper or someone on the boards who is willing to buy one and ship it to you.
Or, you can normally find the on Ebay as well.
Just back from Aulani. Bought he lamp in the gift shop, and they shipped it (from Virginia) for $35
I would try calling them and see if you can order it over the phone
Dreams Unlimited Travel is committed to providing you with the very best vacation planning experience possible. Our Vacation Planners are experts and will share their honest advice to help you have a magical vacation.