Is something missing?
No, that is it. You can dynomat it if you want to, but the door sill is already going to be heavy when you are done with the carpet.
I'm part way through mine. I could have finished it 3 days ago, but I'm being lazy this week.

*edit*
should be in general.....
Look at some of the sill guards and see how far they cover. You might be able to partially cover with carpet then add the sill-guard to give it a finished look. I have changed my interior color 3 times and just pull the pad off, sand and paint the sills and reinstall. Looks like new until i drag my big feet across them a few hundred times...
I do use foam insulation under the sills to get them to fit snug and not move around on the screws. This seems to help a bit.







