Based on Midway Mayhem's recent video. The structure, even though he thinks it is, will not be the clock tower. You can see from the scale of the windows and how the framing is, you can see it is meant to look like more old part of the castle. I know some will be unhappy about this but I'm glad to see Universal sticking with some things be correct regarding the location of buildings. In technicality, the clock tower should be behind the Hogwarts facade. I do know that Hagrid's hut would be back there too but it's a lot easier to pull off that than a whole part of the castle that is connected to the main one being separate.