I couldn't say but I'm guessing your question is rhetorical. If flights were re-arranged within a few hours then, no , I wouldn't expect a meal. On a flight rearranged for the next day or after, yes, I'd like to hope there'd be a special meal.

I suppose that's one more thing for pax to be aware: if you have a restricted diet and are subject to IRROPs you should make your own picnic