Yes, just download and install it. After that go to Tools & Settings -> Server Components and click the Refresh button on the page. You should see new version of .NET there.
I'm having the same issues, did the install, did a restart on the server, went to Server Components and did a refresh and it still only shows 2.0 and 4.0.3???
Is there a different step we are missing?
you can install it using plek upgrades and updates and once install you will be able to see the server consonants. If you have done manual installation then you should be able to assign it using iis application pool.