How do I verify the learned data retrieved while the VSM is running in Learning Mode?
Do I need to save it as traffic in the VSE recorder?

All supported DevTest releases.

When the VSM is in Learning execution mode, the deployed VSI is updated automatically.
To modify or view this update VSI, you will need to download the MAR file from DevTest Portal.
With the MAR file, you can create a new project in the Portal and upload this MAR file, or create a new project in the Workstation from this MAR file.
After the new project is created you should be able to open the VSI and visualize or modify it.

For more information regarding Execution Mode: https://docops.ca.com/devtest-solutions/10-1/en/using/using-ca-service-virtualization/using-devtest-portal-with-ca-service-virtualization/monitor-virtual-services/execution-mode