Most every engine has an over rev, but it doesnt mean that all over rev's are the same. I imagine kawasaki brochures where talking about the quality of the over rev of that engine, not its presence. Good over rev band will hold power steady, decreasing just a little bit, in a predictable way, as opposed to dropping right of.
In other words, its kind of like a power band. Every engine has one, but they are not all the same.