Hi Wood,
check the following article.
When the device is detached, it stays in an unmounted state even if the device is re-presented (that is, the detached state is persistent).
To bring the device back online, the device must be attached.
If you want the device to permanently decommission from an ESXi host, manually remove the NAA entries from the host configuration:
So you could use command esxcli storage core device detached list to check if the host did mount that device earlier or not.
When the device is initially presented (or was manually permanently decommissioned before), it won't appear in that list.
When the device with a VMFS was unmounted earlier and not permanently decommissioned, the naa.ID will appear in that list.
Regards,
Ralf