I would not know where to look for a D concourse in DUS. I remember there were two temporary terminals in the years after the fire, D and E. However, today I am only aware of A, B and C. The A concours is LH's and Star Alliance's world, B and C it the rest of the world. I take at least from the official website that certain gates must exist more than once. There appears to be eg. a gate A75 and a gate B75.