I have run into this issue with many classic children's books. If you're not carful you get a dumbed down version. I have learned to look for additional authors besides the one who wrote the classic. This book has another author besides Kipling, plus the illustrator. I am very liberal in what I allow my kids to read but I don't allow adaptations, with an exception for Lamb's tales from Shakespeare which is a classic in its own right.
The copyright on Just So Stories is long since expired, so publishers/authors are free to adapt the material as they see fit.
I suspect is was altered because it is no longer politically correct to spank children, and in the original version the Elephant is spanked repeatedly. The language is modern and abbreviated, and the wonderful poem at the end of the story is missing.
The good news is that since the copyright has expired, you can download the ebook of Just So Stories (the original) from the free section of the B&N Nook website, or from www.gutenberg.org.
You will be missing color illustrations and the "Read To Me" feature, but you can get the original easily on your Nook.
If you are looking for free Nook books for children with some color illustrations, note that the copyright has also expired on the Beatrix Potter books, and those are available for free as well.