Yup, as sarrowsmith10 said, American publish companies used to flip manga for north american readers. But from what I've seen, it's... well, not that good, some of the panels looks stiff and the flow is kinda weird, if you go and "reflip" the panels, you go, oh so that's what the author had in mind.
So I would draw em R to L from the get go, since it's a contest why not submit the best possible product? =]