We don't know if it's true and if the watch will be sealed (many sellers don't even have the watch yet).
Maybe that Patek will see this and try to find the initial sellling AD and first Patek client.
We don't even know if the info on this add is reliable.
However, I imagine we'll still find some sealed watches, certainly less than before but i don't think they will disappear in one day.
You can imagine we have no clue about if it is true or not, especially as we don't know who is selling (and we don't want to make publicity for them here).
You can report to Patek directly for they make their investigation.