If it is a 97 trans, it will work, just has 1 less bellhousing bolt at the very top. The converter is a different story. The 6.0l uses a fairly loose converter, a good bit looser than any 97 4l80e used. You would also have to keep in mind to order parts for a 97 if you need trans parts as there were several internal improvements in 99(to deal with tow/haul mode), and some electrical changes in 04. My only concern would be running in tow/haul mode, the 97 trans had hollow shafts, the 06 had solid, you could snap a hollow shaft running with the converter locked going from accel to decel. It's not likely to happen, but it is a possibility.
Where does this MIS INFORMATION Come from? If you follow or believe, it is wrong. Sad to read this over the years, but you are mislead by this............ Writer doesn't even read published material by GM.