Depends on the property. Some will and some won't. It's just like on a normal night stay. If you show up early and checkin, technically you're not entitled to breakfast till next morning. However most will allow you to partake that morning.

AS a Diamond I normally just book the regular night, unless day rate is significantly cheaper. Also helps if flight is delayed or worse yet, cancelled. I then checkin early and tell them I'm happy with any room, even a lesser than reserved one. Never been turned away. At worst they sent housekeeping to clean a vacated room so I could be in room within 30 minutes of arrival. This is why I always checkout with the hotel. They know a room is empty and just needs to be cleaned. Thus the next early arriver can get a room.