Our knobs are designed to be used with the posts so that the treatment will have the appropriate projection away from the wall. High end window treatments should project away from the wall and the side of the treatment is called the return. On most of our knobs, the screw length is only about 1 to 1 1/2" so installed directly into the wall would leave no space behind the knob.
We have stock left of the Stewart Knob Long Screw. These are meant to be installed into the wall without a post. Copy and paste this link in your browner and it will show a photo.
https://www.patemeadows.com/Stewart-KnobFinial--Large--3-12-Long-Screw-PLEASE-READ-DESCRIPTION-BEFORE-MAKING-YOUR-SELECTION_p_362.html
If you use the arrow under the large photo of the knob you can see what I am talking about. There is also an illustration under the Ripple Medium that shows the size of the screw for that knob.