I couldn't find any models of the Eggtimer Quasar G3 so I decided to make my own for designing a 3d printed e-bay. Feel free to use it for yourself: https://www.thingiverse.com/thing:6093364
This is a great idea. We do the same thing at work, printing 3D models of circuit boards to give to the mechanical guys to check for fit. It has caught some problems occasionally in the past.
FWIW - I usually don't print the model files - I just bring the model into Tinkercad or FreeCad and then use it so set the location for bosses, clearances etc.