Using the AssetID field you can enable this Admin Console device setting to show custom information (student name/email address/etc) on the login screen.
AssetID can also be updated directly using the GUI
GAM command to bulk update
gam csv devices.csv gam update cros query:id:~theserialnumber assetid ~districttag
CSV Contents:
theserialnumber,districttag
1111,studentname1@domain.edu 1112,studentname1@domain.edu