Yes, they are. The 2006 DVD version includes both the "special" editions and the original theatrical editions. Be warned, though, these are just transfers from the laser disc (except the first few minutes of ANH, which are actually cleaned up film print, and looks nice, and includes the ORIGINAL opening crawl, before they added the "episode IV" title.) These are referred to as the "GOUT" (George's original unaltered trilogy.)
IIRC, it's tough to distinguish between the 2004 and 2006 editions, as their packaging is similar, and, even if you have the right ones, someone might have removed the bonus discs that you want.
http://starwars.wikia.com/wiki/Original_unaltered_trilogy
You can also look into getting the Harmy "despecialized" edition, but this is of questionable legality.