The wall mount is a replacement part for old manual roller shutters. It can be screwed in place using the screw of the old part and is meant as a replacement if the old mount breaks down or yellowed too much. 
I found that 1 screw at the bottom is enough to hold the mount in place.
I printed my model with a 2020 Anycubic printer using PLA and it holds up perfectly for 4 years now. Keep in mind to print it in a different material if it is exposed to direct sunlight at your home.

If you want any special design, feel free to adjust the STL and keep the base geometry in place, you can also reach out to me and I can work that out. Personally I like the flat front face and I think it will look amazing with the textured plate.