The screws are also missing in the TIS image it seems.
In the parts diagram, only 3 of the screw labeled #6 are shown as needed. I assume that would be 2 screws at the outlet of the small turbo and one screw at the bypass valve.
Indeed, when you look at photos of the bypass valve those holes are NOT threaded. The pipe is mostly sealed using o-rings. It seems the case is closed.