It's a LOT smaller than it was in C2 S4. Also, isn't it rather early for Season 4 teasers? We literally JUST got our first update of the season! Also, I don't see any "Stark Industries" branding on it. There's apparently two more on the Island but they aren't aligned (facing a common direction). I think it's more probable then that these are used to tease/ hint at a future update or will be used in a future questline then...