3D Polylines and Named Plot Styles not working

Hopefully someone has an idea about this.

Have a large swath of topography. Most of the lines are simple polylines. A
few are 3D Poly. I am applying a Named Plot Style to the entire drawing that
converts it all to a gray color (for xref into a geology map). All of the 2D
polylines look good (gray) in paperspace (and on paper), but none of the 3D
polylines change their color to gray -- they all stay their original item
color (in paperspace and on paper).

I changed the plot style for all items to "ByLayer" and changed the plot
styles for all layers to a style within my custom stb file. The style within
the stb file dictates a gray color.

Even tried directly applying my plot style to the 3D polylines. ACAD says
those lines now use my plot style, but none of them appear any different.
All still have color.

For one drawing, I could easily just change the item color. But I have 20 to
30 of these to work with. Huge waste of time to individually edit the lines.

Is there something I'm missing when applying the named plot style?

Thanks in advance...

TravisE