you can check if they have any analytics datasets from couchbase.log. They can also do it themselves by checking the metadata catalog using:
SELECT COUNT(*) FROM Metadata.`Dataset` d
WHERE d.DataverseName != "Metadata";
If the result is 0, then they don't have any analytics datasets.
I believe you can access the analytics service stats using this API, but I'm not sure if those stats can give a clear indication whether or not the service is used:
http://ip:8091/pools/default/buckets/@cbas/stats
cbas_disk_used in that list might be the only indication. Those stats should also be available in the UI.