Thanks for suggestions. I think issue lies with older slicer software, 3D cad is perfect. I have also considered making reverse "mold" and use that to hammer out dents of real bezels.
Eh, not to ague but you might be surprised. Lot's of CAD/modeling software "shows" you something different because they aren't designed to actually model for printing etc. You can see it in any STL viewer. Going from an IGS sold to an STL (shell) can be problematic as well. Been there done that :) You might try loading the IGS into blender and exporting it that way.
