Is Surprise Party Amumu not a legendary skin but Surprise Party Fiddlesticks is?

What the title says. It seems that the Fiddlesticks one is legendary (for the snowball event) but the Amumu one isn't. Am I wrong? If I'm not, this is kinda disappointing since I really wanted the Amumu one but not the Fiddles, so now I wont get the snowball mystery skin ;___;