The Peppermint Top Hat (Peppermint Top Hat - Roblox) is listed as “Tradable: Yes” on its item page. However, the item does not appear in the inventory on the trading page, making it impossible to trade.
Here are 2 other limited items that have been sent to me by friends, and they are telling me that they are not able to trade these items either. I also am not able to see it in their inventories on my side.
The dark knight helmet was one of the few April 1st, 2012 items where all of original owners were rolled back, and for that and the other 2 items linked, everyone who currently owns those items got it from a catalog glitch in 2015. Up to Roblox of course but I’m not sure if items that have only been acquired by a bug rather than purchase should be tradable. Would be cool if Roblox re-released those items for actual sale as limiteds though.