That would depend on a lot of things: the restaurant itself, whether what you want to get has a dinner variation, whether those ingredients are even available for dinner service (if they haven't been put away as part of the dinner prep), etc. etc. You won't really now until you ask. Not sure which restaurant specifically you are asking about, but I have found that at Disney restaurants in particular, if they can do it without a big disruption to their service, then they will try to accommodate. Never hurts to ask.