Having a strike out is not helpful or informative. If there's debate that despite it being officially listed on the forums as 5k but may actually only be 4k, we can say that. if it used to be 4k, that doesn't really "add" to the article by having it there, and should instead be in a "Historical" or "Trivia" section.
So my question is this; why is the 4000 there, and what's a better way we can deal with it; if it should be removed we can remove it, if it has historical significance, let's move it, and if we aren't sure, let's clarify.