An article over at Joystiq.com suggest so
-- "When we learned that the PS3 version of The Elder Scrolls IV: Oblivion would not feature the majority of downloadable content found on the Xbox 360 and PC versions of the game, it was a blow to fans of horse armor everywhere. This weeks episode of The 1UP Show (02/02) provides the follow-up hook as Managing Editor Garnett Lee relays a juicy bit of info from Bethesda. As it turns out, it's due to a memory limitation with the Playstation 3 itself."
Read the full article for more details on the PS3, Xbox 360 and rumored Wii versions.