OemKey from the command line?

Is there a way to use OemKey from the command line to detect the presence of a key in the BIOS? We have many workstations that were were bought with a 8.1 to 7 downgrade license; I'm trying to find a way to audit them and identify which need an upgrade license and which already have an OEM license. If I can run it without a gui, I can script it. I don't even need to retrieve the license, just know that it's present.