It showed up in my inventory, but unlike the skins that I have accumulated for various ships, where I can right click and see an option to activate the SKIN license, the hats have no such option that I saw.
I get show info, view market details, sell, buy, create contract, find in contracts, add to market quickbar, and trash it. That’s it.
I tried just double-clicking the hat but nothing happened.
I went back to the tailor in a station but there were no hat options for my character there, so it didn’t, as far as I could see, automatically unlock by my just having it.