Yes, some newer Twin Otter aircraft do have a wire running from the top of the cockpit to the top of the tail, as do some legacy Twin Otter aircraft. That wire is a high-frequency (HF) antenna, which allows the flight crew to use an HF radio.

Since Viking revived production of the Twin Otter aircraft in 2010 up to and including 2015, 84 Series 400 aircraft have been delivered and put into operation worldwide.  These 84 Series 400 Twin Otters have been delivered to 31 operators in 29 countries.