Yup they didn't start making proofs for capped bust halves until 1818.All are extremely rare with only a dozen or less for each date.
Proof bust halves are ultra rarities. Most of us can only hope to ever own one. They are in the six figure range.
It's a pretty nice strike, like they said 100% couldn't be a proof based on the year. But also is looking somewhat harshly cleaned to me...
Much better than usual strike for that die marriage which normally have a very weak wing on the reverse. No proof, but a nice example of an early date CBH. Even with the cleaning I wouldn't kick her out of my safety deposit box.