Let's think about this a minute...
Lost nuke at the bottom of the ocean, subjected to salt water corrosion for over fifty years, possibly leaching hazardous radioactive waste into the water.
I don't know about the rest of you, but were I on a team trying to locate and evaluate the potential for recovering said nuke, I wouldn't be diving atop where I thought it might be. Radiation can have some really nasty effects on the human body, and my inclination would be to use remote submersibles with cameras to try and locate it, rather than risk radiation sickness or cancer from exposure to a leaking bomb.
Documentaries aside, my own personal opinion is, if they're diving for it, they're fairly certain they're NOT in the right location. At least, I wouldn't risk radiation poisoning for the sake of filming a documentary about a missing bomb.