If you want to centrally manage the Chrome extension (included in the full SBA and also part of the SBA for Browsers), then the PCs need to be part of any domain at the time the agent is deployed. This way, the Chrome extension will be added and managed by the Endpoint Management.
If it's not part of a domain, then you can add it since it's available as a standalone package and also available in Chrome Store. This way you will be able to centrally configure it using some deployment tool capable to deploy .reg files (or through GPO if they would be part of a domain), or also manually, however it will not be managed by the Endpoint Management (including the logs).
Hope this helps!