No, it specifically checks that it's not on replay mode to trigger the event. Also, not sure how the save replacing works, haven't done it yet luckily. Maybe renaming works, just to be sure backup the old one or make a new save in the page and slot, and then replace that one with the new one.
Here's two saves, just to be sure. Keep in mind they're green-route. 56-6 is on Sunday morning, navigate through the GPM in the afternoon to get the new event. 57-1 is in the beginning of the new event itself already. Be careful, since the flag from the new event persists through saves, if you want to watch the event and not activate it, just watch the event until Amy mentions the word lungrot, watch more at your own peril, because if you reach the go to menu, the flag will be activated forever.