This is a 65mm (C-band) LNB holder for Mabo 180cm offset dishes.
Additional material:
1 M5 washer
You may be able to do without the nuts and washers tentatively, because the bolt threads will cut into the plastic and hold steady.
OpenSCAD sources may be found on GitHub.
The author marked this model as their own original creation. Imported from Thingiverse.