Can you configure APN and WIFI via XML File?

I have a customer that plans to stage a large number of TC55 JB-GMS Devices. Currently it's a manual process. They are looking for a way to configure a custom APN and WIfi configuration programatically without using an MDM.

I'm am also assuming that the GSM SIM would have to be installed to program the custom APN.

They are planning provisioning the SIMs at a later date. Not sure it that will be an issue.