To determine if you are using a ChromeOS Flex device, you can use the following methods:
Chrome Management Console
There are various ways within the Google console when looking at your devices to determine if a device is using ChromeOS Flex or not. These are your way to indicate:
The word “Flex-” will appear at the start of the device name / serial number.
The ‘Serial Number’ value itself is shown as a MAC Address.
The Platform version name will always be reven (that is the code name for the flex OS flavour)
Via the configured ChromeOS Flex Device
You will know if the device uses ChromeOS Flex as when you start up the device it will show an image which states “ChromeOS Flex” this would indicate that this device is using ChromeOS Flex and not standard ChromeOS.