I think the best way is to check content of classpath directory in your agents' home directory.
It should look something like this, the exact list depends on the version, but the versions of the jars should match* the version of your Bamboo server. You also should not see any duplicates (same jar in different versions)
*) There are exceptions like dotnet plugin for instance, but you get the point.
ls | grep "atlassian-bamboo-*"
You can also check the agent logs; if agent updates correctly you should see sth. like that:
[AgentContext] Important agent classes have been updated, the agent will now terminate to pick up the latest changes.
[ClasspathBuilder] Server publishes 341 files, we need to download 341
G’day Bamboo customers, The wait is almost over! We are in the final stages of work on the first release of Bamboo Data Center, our self-managed enterprise offering of Bamboo. This Data Center offe...
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