Exactly as Mich said, does the vehicle have Navigation built in? Navigation for that year was an upgrade/option and was not standard, even on the LTZ model. Only in 2015 was Navigation starting to become standard on LTZ's. Now, when you turn on the radio and go to the home screen, is the "Navigation" icon showing (grayed out) and is the Sirius/XM also showing (grayed out or color)? If so, that radio has the capability of being upgraded to the GM navigation system. There are modules you can buy from GM and install yourself, or you can have the dealer install it if you're not comfortable taking parts of the dash apart, and there are third part modules. It is also possible they have the navigation in the system just turned it off in the settings and are using OnStar, which is just displaying the turn by turn similar to when navigation is being displayed on the gauge display. If this was new purchase, their window sticker would clearly state "MyLink with Navigation" on the features. They can also log into the Chevrolet Owners website portal and it would show them exactly what radio system is installed in their vehicle.