GavoTrav,
That's correct. The "Pluggins" section is dynamically rendered. There are several WHM Pluggins, some offered by cPanel, but most are provided by others and must be installed via command line. Some hosting providers will have WHM Pluggins already installed for you when they lease you the server.
Sometimes these pluggins are referred to as WHM Addons. And for further confusion, the ones that cPanel offers on their mirrors can be found in WHM under "Main >> cPanel >> Manage Pluggins" (inferring that their utility will be limited to the cPanel end-user context, which is exactly true. We call such things "cPanel Pluggins" and they are entirely different in nature).
At any rate. It's like the technician said: If your newly provisioned server doesn't have any pluggins install, yet your old one did, you will see a discrepancy (like you've reported here) and you will need to install the...whatever they were.
Regards,
-DavidN