I'd be very surprised if it hadn't been picked up long ago by a navy salvage operation. While the mechanisms would probably be inoperable, the fissile material would be of interest to certain unfriendlies these days.
Lost nuclear bomb possibly found Device dropped in ocean off Georgia during Cold War Monday, September 13, 2004
Government experts are investigating a claim that an unarmed nuclear bomb, lost off the Georgia coast at the height of the Cold War, might have been found, an Air Force spokesman said Monday.