Well done your research worked.
Have You Tried My Garmin My Dashboard ? To see if the device has in fact got maps for life.
You might need the previous user's username and password.(Or get the previous owner to log in and de-register it for you)
The Tools for Map updates are Garminmapupdater and Garmin Lifetime Map updater. (From Garmin.com)
Webupdater does not update maps only firmware, and Voices etc etc.
If the device does not have Map Updates you can get maps here at Noeman.