What you are seeing seems to be what is called a "Darwin Descriptor". These are used by the installer to provide resiliency and facilitate repairs. See aa302344(v=msdn.10).
With respect to COM registration it gives an example -- "When an application creates an instance of this component through normal COM mechanisms, Windows Installer "hooks" into the process in just the same way we saw it do with file associations. Notice in Figure 3 that this time a "Darwin Descriptor" is stored in the InprocServer32 registry value for our component's COM registration. Again, this information is decoded and used by Windows Installer to ensure that our component is properly installed and configured, performing any repairs as needed, before finally returning an instance of your component to the calling application."