SM_ColorCalibrator missing materials

Apologies for this novice question but no ‘Beginners’ section.
I’ve dragged the SM_ColorCalibrator Static Mesh into my level but it is missing any materials.
So I applied the M_ColorGrid material but it applies to the entire object, cube AND the 4 spheres on top.

If I open in the Mesh Editor I can see only 1 material slot available.

Can someone tell me what I am doing wrong?
Is there a way to re-import the ColorCalibrator into my Content Browser so the materials are correctly applied?