False.

The Blu-Ray crops the IMAX 1.44:1 scenes to 1.78:1.

The DVD features use the full 1.44:1, but pillarboxed in a 1.78:1 frame. Also, they don't include every IMAX shot, just the six main "sequences."

I know that the 1.33:1 version shown on HBO (and possibly the fullscreen DVD) uses more picture information on the top and bottom than the Blu-Ray cut does, so my assumption is that they're 1.44:1 cropped to 1.33:1, which is much closer to the original version.

A proper DVD IMAX cut would have to convert the DVD from 16:9 anamorphic to 4:3 letterbox, and the IMAX shots would be replaced with 1.33:1 fullscreen shots from the fullscreen DVD using the Blu-Ray version as a guide (assuming the fullscreen DVD does what the HBO version did).

The DVD special features could be used to add the rest of the 1.44:1 information to the sides of the 1.33:1 version. This would mean that the major IMAX sequences would be at proper 1.44:1 (with very thin bars on top and bottom), while the random IMAX shots not included in the special features would be 1.33:1.

Doing it in 4:3 letterbox would recreate the IMAX experience more closely than the DVD features format that switches from letterbox to pillarbox. I would say the Blu-Ray should be the definitive IMAX cut for 16:9 TVs, while this theoretical version would be the definitive IMAX cut for 4:3 TVs.