Is the Starcraft 2 Collector's Edition Ultralisk skin the same as the Leviathan skin?

I’m considering purchasing some skins for my StarCraft 2 account.

I will likely go for one of the packs to get a full set for ~$20, but I noticed that I could get the digital edition for about the same price, which would give me an Ultralisk skin (among all the other goodies) for about the same price.

Is the Leviathan skin and the Special Edition skin essentially the same thing for the Ultralisk?

I think the Leviathan might have slightly longer spines, but is that the only difference?