I don't know for certain on whether you can get it, but I can tell you that my Onion set will not go into the Armoire in the inn room. I am guessing that means that it is not currently obtainable. It seems to me like the kind of special item that would fit in there if you could get it in ARR.

Other things that will not fit but I think they should are the old holiday clothes, like the santa suit and egg hats. I figure again that it is because they are not obtainable in ARR, so no one thought to add them as a possible Armoire item.