As much as I hate to drop this hat, the sale for this doesn't help it.

Only sale that doesn't involve using higher-tier hats.

Sale #1:

http://www.tf2outpost.com/trade/26509976 - Traded for a Bubbling HazMat Headcase (75)

Note: HazMat was recently traded for a Frostbite Party Phantom. It does have some standing at 75.

Seller's Backpack:

http://backpack.tf/profiles/76561198060609260?time=1438153200

http://backpack.tf/profiles/76561198060609260?time=1438498800

Other one was used in a sale for the Green Energy Skullcap. May revise this evidence.