I don't know where you found that picture but it looks a HECK of a lot like the sneak peek image. Though, it's not lit in the sneak peek if that's what it is, but I wouldn't call that overwhelming evidence that it's not a lighthouse.
The part that is catching my attention on the sneak peek is the little gap in the structure where you can see the sky/sea behind it. On the right of the structure, at the middle section. It looks like there's a thin vertical beam holding the structure up. What could that be?