As the PP said, it can work, but it can also not work. If the venue is full/crowded, they are unlikely to let you check in that early. I've been there when they were telling folks they could not check-in until 15 minutes before their ADR at BOG, 'Ohana, Le Cellier, Sci Fi, and CRT.
Given that MNSSHPs don't start for about two more months, you still have plenty of time to search for an earlier ADR. I would keep looking because people's plan do change and ADRs do come open. It would be better to have an ADR for the right time opposed to hoping that they can accommodate you early.