I saw one on a college student at the grocery store this morning, same color, but a two-button model. Sorry to say I saw a large display of these olive drab caps in the fall, at Target, I think. I made a comment they're trying to bring Mao back. Now that Sarah's wearing it, I like it way better.
Hilarious! That's the first thing I thought, too!
Check THIS out!
It's actually called the "Mao Hat".
HOWEVER... this is not the hat worn by Sarah. Sarah's hat looked like wool and had no strap across the front (above the brim). I think Sarah has a (so far ) secret source for her hat, because nobody that I'm aware of has come up with the exact same model yet.