Tommy!
Thanks for posting but yes it's much too late. My advice is to bring extra food for that person, however there will be a slight chance we will have some food remaining after all registrants have gone through the chow line, but we can't guarantee anything.
Check the registration packet pick-up booth where Christine (Mrs Crawler) should have a late-comer sign-up sheet just in case some food is remaining. Get on that list early (Friday afternoon if possible) for the best chance of extra good. But I still recommend bringing some food for that person just in case
BigMike