You have to upload your progress as you go. It helps everyone know that you didn't just buy a model last minute and enter that. As far as I know that's the rules of every competition like this everywhere

There are a lot of entries where the person hasn't completed and so they just have a whole lot of uncomplete screen shots and renders, if that was your concern.

Even if you don't finish someone might give you a helpful tip or feedback, so all is not a loss.