I too liked the look of these, and bought a set from my Ford Dealer in the late 70's and installed on my '66 Coupe. I then bought a set from my Dealer in the early 80's for my '67, which I will install on it after painting. Neither set came with any instructions. Being over 35 years ago that I installed them, as well as the fact that back then I didn't document things as well as I do now by pictures, I don't remember the exact installation process, other than I do remember having to remove and reinstall the standard sill plates. I can't remember if any of the Accessory mounting screws show, and unfortunately, my '66 isn't readily accessible to check.
If anyone replying to your post has installation instructions, I know that I, as well as you, would surely appreciate it if they would post it.
I have attached a "catalog cut" from the 1966 Accessory catalog as well of pictures of the NOS set I have for my '67.
Bob