I know almost nothing about unusual trading, but as far as I can see, this is pretty legit. Also the poster has a ton of accepted suggestions, so I trust him.

The 2nd link looks like the guy is just quickselling it since he has another pyro unusual and doesn't want the stormy beanie, 1st link he's also quickselling it. There's a difference between a b/o and a quicksell price, but stormy is decreasing in value so I'm iffy about this suggestion.

@Laggy, even if someone has 10,000 rep you should still look at the links and make sure what he's saying is legit. Not just assuming so because he has that much rep/approved suggestions.