Sturgeon boy, MIB 2 infotainment units were fitted to the mk7 Golf from model year 2016, the build of MY 2016 models would have commenced from week 22 of 2015.
Link to Navigation and Entertainment units on VW's website below which gives a summary of the features of the various infotainment units. This should help you identify whether it's a Discover Nav Pro or not by asking the seller if it has the Nav Pro features listed.
http://www.volkswagen.co.uk/technology/navigation-and-entertainment-systems
If you're considering fitting a used Nav Pro unit to your car, be aware of the component protection (CP) issues. Units are coded to the original vehicle they were fitted in as an anti-theft measure, to help minimise the sale of second hand stolen units. For a second hand unit to work in another car, the component protection would need to be removed and unless things have changed, VW dealers won't remove CP from used units as the dealer wouldn't want to be associated with enabling a used infotainment unit from an unknown (possibly stolen) source.
I dare say there may be some people / sellers of car sound systems that have found a way to hack these units to remove CP but it could mean that not all the functionality will work on a hacked unit.