We discovered as much when retail copies of Saints Row: The Third arrived for review on both Xbox 360 and PlayStation 3 last week. After booting up each and looking around thoroughly, we can assure you that there's no content difference between the two versions. We contacted THQ, who today offered a "No comment" to our inquiry.
It stands to reason that the "exclusive mode" -- which apparently featured the game's "signature weapon" (a dildo bat, naturally) -- could have once been the game's take on wave-based co-op multiplayer: "Whored Mode." That mode is currently a part of the Xbox 360, PlayStation 3, and PC versions of the game. The publisher would neither confirm nor deny this suggestion.