That looks like the bolt for the auto. From memory the equivalent on the manual does not have a socket-head but the slightly odd flat head which locks in to the casting of the bellhousing, and is secured by a nut on the engine side. I'm not convinced that supersession is correct.
The only time I've seen this is on Vera's though, which was a few years ago so my memory may be faulty. I will check a manual gearbox tomorrow
