That has nothing to do with licensing, the phone itself doesn't have a license, nor it would configure automagically by itself, if they're showing a configuration after a factory reset, they're getting that config from a call agent or a TFTP where the config files are.
Look at the DHCP config they're getting and most likely they will be pointing to a TFTP, and that's where they're pulling the config from.
There are plenty of threads in the community regarding Cisco endpoints with 3rd party call control you can use as reference, you'll need to find out if the devices are running 3PCC FW or enterprise FW to find out how to configure them. If they're running 3PCC you'll get a nice GUI to manually enter your configuration, or point to a central repository where you'll hold the configuration files. If you're running enterprise FW (which is meant for Cisco call control) you can still get it to work, but there will be no config GUI, and you will have to configure all your devices formatting the files as if they would come from a Cisco call control, which is what the phone expects.
HTH
java
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