I sincerely hope it is that simple - but bitter experience tells me that anything to do with red tape in the GCC - especially cross border red tape is fraught with difficulty - and here you are crossing 3 borders. Believe me when I say that the Saudi Border customs will treat you as a westerner completely differently from other GCC drivers - be warned!
It goes without saying that you lie through your teeth abouth the value of your car - unless of course you enjoy paying tax.