Generally, you can't lower the price of a hat based on a duped sale. There are exceptions, but this hat doesn't meet the requirements for that; for example, one of the criteria is "There are NO sales of the clean version in the last year".

Having said that, the rules also mention a threshold for "duped doesn't matter" of 30 keys. But depending on how you look at it, this is a 35 key hat not a 30 key hat.

Source:

https://forums.backpack.tf/topic/6033-rules-for-unusual-price-suggestions/