The Dublin service is still 77W for the foreseeable future.
The AFTERNOON service is being looked at as a possible A380 flight. If it does occur it will only be the afternoon service because the Airport cannot handle the 380 for a lunchtime arrival. It will be parked at the stands on the eastern side of Terminal 2 (i.e. by the threshold of 28,) as this causes the least disruption, and at a quiet time.
How do I know? 2 reasons. 1. I have spoken directly to those who plan this. 2. Chatting to a friend who owns a large travel agency. Nothing is loaded for the 380 to Dublin. 77W is still there. If it was 380 on the 17th of March like vfenext claims, it would have already been loaded into the system.