Correct. If you've already made the character account and joined, then no, you couldn't participate. And we ask that you be in a position to make the character fairly soon after you've won. If you can't, then we would prefer you wait until the next slot, so that you're not taking it from someone who is able to make a character now. You also aren't allowed to win a slot and then 'hold onto it' forever. It's supposed to be for people bringing in characters now.
Does that answer your questions?