Yes, the purpose of the manifest file is to tell windows to use Common Controls 6 if it's available, regardless of what version then application was compiled with.
And regarding quwiltw's comments, adding a manifest file to the IDE is a very bad idea. It actually changes the way the IDE serializes resources, so you'll never know there's a problem when you open your solution on your computer, but as soon as you give it to someone without that manifest, they won't be able to read the serialized resources properly.