I also have a 6.5 Uconnect. I have had the car since last August and was pre-registered with just 10 miles on the clock. I understand that my car was built late 2016 and was probably an unsold 'launch' model as it had all the extra bits on it apart from the launch badges. I did carry out an over the air via the internet a system upgrade but my understanding is that this had no effect on the maps. I have been following the Uconnect discussion on the forum very closely and it appears there is an map upgrade available for the 6.5 but only through a dealer or Fiat workshop. This upgrade apparently gives proper TomTom mapping via internet using a mobile phone to connect.
I have approached a couple of Fiat dealers, the one where I got the car and one more local to me and they cannot confirm if there is an update or not though several owners on the forum have posted photos showing a different screen to mine.
Unfortunately there are not many vehicles with the 6.5 fitted and as a result dealers are not very knowledgeable and calls to Fiat just say go to the dealership.
My map version number is 15. something and the new one apparently is 16. something.
I am waiting for my first service that wont be long now and if they hook the car to the computer system it should upgrade, I cannot confirm if this will be a free upgrade or chargeable, time will tell.