We'll know in a few hours. If he wins Ohio and Florida he'll almost certainly get 1237, the rest of the states aren't winner take all so Cruz would have to win every state by a ridiculous margin for Trump not to get 1237. If he loses one or both then yeah probably no body will get 1237, since Kasich/Rubio won't drop out and keep on stealing delegates.
But despite what other people say, I actually think Trump can win a contested result. If that happens you actually get to talk to and persuade/negotiate with the delegates, which the Donald can do better than anyone.