Almost. The anime sounds more like a mix of "homage" to history, in fact almost a side history. Or perhaps even the anime is a meta-story (since the very fact of using "time travel" may suggest that the anime has intentions of altering something published in the manga).
I read the manga today and most of some of the plots in the anime exist in the manga, but with the anime's exclusive character (Konoha) acting in place of the current characters in some key parts of the story. Furthermore, I could be wrong, but the details about "eroge" that the manga even plays with (Meiko arguing with Gomikawa about erotic arts for example) end up kind of omitted in the anime (Konoha is younger than Meiko, by the way).
Until then, I can say that the role that Meiko plays in the manga (she is one of the protagonists and also the narrator) is played by Konoha in the anime.