It was actually sold for Australium Killstreak Eyelander + 8 keys . Backpack of seller after the trade http://backpack.tf/profiles/76561198125004563?time=1421049600

From the looks for the current owner's backpack, it doesn't seem like the current owner is a collector of the hat. Since the sale only happened yesterday, you will need to wait for a month to see if this hat is resold unless you can prove that the current owner will not resell this in the next month.

With reference to the rules

http://forums.backpack.tf/index.php?/topic/6033-new-unusual-price-suggestion-guide-the-cheat-sheet/

Any hat can be priced based on a single sale if ALL these criteria are met:

- There are no other recent sales in the last 3 months

- The hat went to a collector or person who intends to keep the hat. A collector can be identified by looking at the person's trade history, item history of similar unusuals in the backpack OR if the owner has not resold the hat 1 month after the sale occurred.