No, and you will get better results by dropping your comp in a render comp that is the right size and then scaling your existing composition to fit horizontally, then rendering that comp.
By the way, the comp sizes listed here are both completely illegal MPEG sizes if you are going to any kind of standard output device. You should stick with the presets unless you know exactly what you are doing and have specifications from your client or a system provider that you must follow.
Thanks for the info!
Oh yeah, I know the dimensions are crazy.