This seems like a non issue to me and I say, so what if he wanted to show respect to another country's leader. Not a big deal at all. With that being said, it clearly appeared to be a bow, so I don't like the fact that Washington is trying to lie about it. But still, a non issue.
I must say this thread is extremely ethnocentric. The Saudi King would not bow to Obama because he is older than Obama. Duh. Dammit people there's different cultures all over the world and bowing does not have a universal meaning.