Thank you to all of those who point out that I made a mistake. It's the FIRST thing I realized.
He said he mounted it on his camera and "it does function". He says it autofocuses. I might take it to a repair shop, if the AF motor is functional, perhaps it won't be cost prohibitive to repair.
I have an old Nikon I could try to mount it on, to check the AF motor. No way I'm attempting this on my D300. The lens won't even sit flush with the mount on the body before you rotate it, as if the lens is too big to fit. Functional indeed.