Apple released iBooks 3.1.3 for the iPhone, iPad, and iPod touch late on Tuesday in preparation for the launch if iOS 7. While the update does improve iOS compatibility, it didn't drop its skeuomorphic look and is sticking with its wooden bookshelf interface.
iBooks sports the same old look, but it is iOS 7 compatible
The update notes also say version 3.1.3 improves iCloud compatibility, which most likely means better sync support for the upcoming release of iBooks for OS X as a part of Mavericks.
iBooks is free and is available at Apple's iTunes-based App Store.