I'm pretty sure they are all prerequisites for eachother. So CCT is now Jamf 200 so I assume you would have to take Jamf 300 before you can take Jamf 400. At least thats what I had to do back when they were the CCT CCA CCE respectively.
The 350 is a great course to take as well. It focuses on the server build instead of end point management. Unfortunately they are no longer providing any instructor led 350 courses but they will have all materials on line some time in the near future.