The MAC address for any network device is in general not a way to identify the device the ethernet is connected to unless you’ve already examined which device type it is and created your own lookup table of MAC-to-type. You might be better off if you give a use-case of what it is you want to accomplish.
All Jetson modules I know has an onboard ethernet controller. That controller is often used directly for consumer devices.
I am often asked how this and that product is working, and I usually take the MAC address as a hint. That often leaves me with a company name like Qualcomm or Nvidia
It would be usefull to be able to determine what Jetson is used when Nvidia pops up.
I don’t think that is possible, although some companies might use a given MAC address range (a range which might change). If you want a guaranteed answer, then you probably have to be able to log in to the Jetson (there might be some corollary in recovery mode).