This is an ACROBAT option not a SolidWorks option.
When you open a 3d PDF it open in DEFAULT DISPLAY MODE and you have to turn on the Solid Outline. I know of no way to store this with the file
in this context:
there is a pending problem with "solid outline" in 3D-PDF export (SPR 849068).
Prio is still "medium" and you all can help to lift it to high if you report to your resellers.