I think maybe we would have. Even probably. Only because our division is just so awful. But I don't think we would have won into the playoffs, and certainly not the SB, and I think we do have a very solid chance of doing so this year.
Having a Manning makes the entire team better. Special teams, we get up the field further, and our kicker can pin them deep. Defense, we get ahead, and we can actually pass rush, since they will be passing more, not rushing. Just having one player can change the entire team.
So it would not have mattered had we won the division. We'd have still been either one and done, or definitely two and done. Now we have an actual chance to win it all.