The notification of the rescheduling of the service, linked to the flight details saying it's a 747, and verification by attempting to book it from scratch which also shows the flight as a 747. So that's definitely changed - I'm assuming it's more likely that the change is correct and the seat plan is out of date though I appreciate either is possible.
It could be that it was switched and then switched back to a 777. I've yet to read anyone saying the the seatplan was wrong, but you could be right. However, if I was betting, I'd say you're currently on a 777.
Let us know
Alternatively, let us know when you're flying and someone within KVS/Expertflyer access might be able to give more details.