I'm using the V2 version. the binaries are from the stock kernel of cm11S (you can find it here http://forum.xda-developers.com/oneplus-one/general/official-stock-color-os-cm11s-flashable-t2844348)
To find the file, navigate in META-INF/com/google/android folder of the kernel zip, then here you can find two files. One is update-binary
As you were talking about a stock kernel, I grabbed the stock boot.img available on the stock mirror thread and began to try to extract it!!