It is to be noted that the Doors 'free' 3 track pack can only be retrieved from the Rock Band Store in the game menu for RB3.
In other news...
Imagine This - John Lennon Coming To Rock Band 3 As DLC
It's not even out yet, but the DLC keeps on coming for Rock Band 3 anyway. Joining Bon Jovi, Billy Joel and The Doors and the 2000 tracks already available from the Rock Band library, is John Lennon's 'Imagine' album in full, which is a perfect fit for the game's keyboard.
"The songs on John Lennon's Imagine run the gamut from beautiful piano-driven ballads like ‘Jealous Guy’ to all-out guitar rockers like ‘Gimme Some Truth’," said Paul DeGooyer, senior vice president of games, music and programming for MTV Networks. "It's an incredible musical statement, and a real workout on keyboard, guitar and vocals in Rock Band 3. We're very excited to confirm it as one of the first downloads for our new game, and to help our fans celebrate John's 70th birthday with its release."
Lennon's 'Imagine' will be among the first albums to be released for Rock Band 3 and will be available post-launch in the US on October 26th and October 29th in the rest of the world. Pricing and exact details for 'Imagine' are still to be confirmed.