NO. That would be an exception. If you create any graphic that MATCHES a standard non-square pixel size, then FCP will determine that that graphic is non-square and treat it as such.
If he were creating a logo for example, he would create it at whatever size is appropriate. If it were a wide logo it might happen to be 800×200. If you wanted something huge that you could zoom in and pan and scan, you might create a logo or graphic at 2200×2000. These are arbitrary numbers. FCP would see them as standard square pixel graphics sizes, and add distortion (in the motion tab btw) so that they match your non-square pixels in your seqeunce/video.
It’s that simple. But if you create graphics that match a video frame size, 720×480, 720×486,etc. then FCP will assume you’ve done the diligence and already converted it to non-square pixels. It will not add the distortion. If this is incorrect, you can add the appropriate distortion in the distort area of the motion tab.
To make it more confusing, PS actually supports square and non square. You can simply create in a 720×480 NON-square document in photoshop as well.
HTH