There are two versions of this model: one with size indicators for the hex keys and one without these indicators. Both versions have 2 countersunk holes for screw mounting it. You might need to use some support material, depending on how good your 3D printer can bridge.
Support
If you'd like to support me for the 3D models I distribute for free, you can use the following AliExpress affiliate link: https://s.click.aliexpress.com/e/_AoUC8h
Whenever you buy something through this link, I get a small kickback without costs for you :)
The author marked this model as their own original creation.