Yup, that car has the 81P "comand with navigation update" option. But its over 3 years old now (delivery date 30/11/2011) so they won't be able to generate free map PIN codes anymore. (unless it hung around the dealership for a while and wasn't registered for a couple of months and I can't see that information)
The trouble is that firmware and map updates take ages, use up a bay, a diagnostic machine, a stable power source and a technician checking regularly. There is also risk of component failure during firmware update (which on an out of warranty car is the owner's problem) and sometimes you have to restart map updates.
So dealers don't really like doing firmware updates, and will charge ££ for firmware and maps when out of warranty.
If you have a Mercedes extended warranty you should be able to persuade them to at least try updating the firmware as they should get paid by MB for the work.
Cheers
Richard