Does it? I'd say it only means that the updated outro was probably filmed recently.
But that in itself suggests that it wasn't planned far in advance. I mean, the whole thing has an abrupt quality to it. The trio didn't get any kind of swan-song myth or on-camera farewell, which suggests they didn't know they were leaving until after they'd finished taping for the season.
The trio not being in their own farewell still makes me think they were dropped a while ago, before the refilmed outro was made.
But you just said, the sequence was probably taped recently. So the latest date they could've been let go would be only slightly less recent.