I love this question. CM should own and support the version control system so in that sense we often "own the code". I have had this role many times. I usually own process engineering and process improvement because it is so essential to our jobs. In the ITIL v3 framework Release and Deployment Management (RDM) is responsible for ensuring compliance with release management processes.
CM should be teaching people HOW to do code reviews and then running the code review session. We are probably not the best choice to be a reviewer which I think is what you were trying to get at. But you could be the facilitator, the narrator, the scribe or even another reviewer. (Contact me if you want a process model for code reviews)
In security situations, you might be working with the information security director to code scan the software without the developers even being aware! (Yikes!)
glad to discuss further
Bob Aiello, Technical Editor