You can replace the ocio configuration from blender, and use the one used by the author of Filmic BenderBlender directly
https://sobotka.github.io/filmic-blender/
Alternatively, to use the Greyscale look, you can manually edit the config.ocioconfig.ocio file in the colormanagementcolormanagement folder and add the following stanza in the lookslooks section:
looks: - !<Look> name: Greyscale process_space: Filmic Log Encoding transform: !<MatrixTransform> {matrix: [0.2126729, 0.7151521, 0.0721750, 0, 0.2126729, 0.7151521, 0.0721750, 0, 0.2126729, 0.7151521, 0.0721750, 0, 0, 0, 0, 1]} 