Chocobo Shirt?

[Ziyyigo-Tipyigo]

The real question is: If instead of buying the expansion, we buy the full edition (which gives this item) and use the code to add the expansion to our existing account, do we still get the item?

That's exactly how I got my Destrier Beret.

Keep in mind that the "Reward Code" for the shirt will be separate from the "Registration Code" for the expansion/collection. All you'll need to do is add the "Reward Code" to your existing account rather than a new one.