I have a feeling that there is a very limited supply of the accessory, and that they've already taken more orders than they'll be able to fill. The game spent time on the top ten best-sellers in videogames, so I hope that nobody is counting on receiving a freebie.
Does this game actually teach you about the underwater sea life?
It probably can. In the first game, I believe that you had some sort of fish journal, and every creature that you interacted with would be logged into it. When you spent more time with the creatures then a couple more pages of information about them would become available. I've no idea how accurate the information or behavioral patterns are.