I wouldn't cull just because a juniors coat was too harsh, or a Jr Opal did not have a Rufus band, or a Jr Castor did not have rings in the right order, or if a Jr molted badly, or if it did not make Jr weight. All of those things can be rectified as it ages. Now if was a senior coat that would be a problem. It's only a three week old kit. At Jr prime, it may not even look like this. I don't really worry about showing as a Jr anyway, Rex take so long to grow, there's not much to competition at the Jr level.