No, the important detail here is that you can't see those 4 different highlights on the Kindle's E-ink screen. Amazon has given the iOS app a feature that the Kindle will never have (unless there is a color Kindle coming).
I think this adds to a point I made last week. I wrote a post about hardware no longer being the determining factor for ebook sales, and one detail I used to support my argument was that Amazon was giving the Kindle apps all the same features as the Kindle hardware. Today Amazon proved my point by adding a feature that the Kindle can't have.
On the other hand, perhaps this is a sign that Amazon has a color Kindle on their product roadmap. It would explain their rumored interest in Liquavista, and even if it's not true one can always dream.
And in other news, Amazon also added a new end of book reminder similar to what is currently included on the Kindle Fire. When you get to the last page of a Kindle ebook, the iOS app will now suggest that you write a review, rate the ebook, or share with your friends on Facebook and Twitter. The app will also suggest other ebooks you might be interested in reading.
You can find the app in iTunes.