Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
That's not "Navy blue" (Dark Sea Blue) - it's Dark Gull Gray (aka "seaplane gray" aka "engine gray.")
The Navy stopped using Dark Sea Blue on aircraft in 1954-55. The S-2 first flew in 1959.
I don't recall ever seeing a dark sea blue skin for that model. If someone painted it blue they made a mistake.
Overall dark gray is also a pretty spiffy scheme, but I'd like 'em better if they were Dark Sea Blue.