In fact it's the first hat that showed up at hats dot com. They have some really cool caps and hats here.
Castro's hat has a band over the bill. The one on hatsdotcom has a band over the bill. Palin's does not have a band and it has three buttons. Her bill runs all the way around to over her ears. The other do not.
It's just a hat. I have pictures of my mother wearing a hat like that 70 years ago.
IMO it's kinda ugly on her, actually... doesn't suit the shape of her face at all.