Question on color shade of instrument cluster pieces

RedFish said
Earlier inst' housing were flat white inside. Their yellowish incandescent bulbs were totally encased in a blue tint diffuser to create a coke bottle green lighting. Where this changed to a flat piece of blue film in front of the bulbs they changed the housing interior to flat blue creating the same appearance. Many of todays owners like to change to LED bulbs and dump the blue tint to get a more modern brighter whiter lighting.
All gauge screens, etc.., ( including aftermarket ) are flat black or white. Light bounces around. Gloss causes glares.

Exactly.
I painted my cluster backing metal gloss white and used an LED strip for the backlighting.
Also replaced the speedo lens with lexan.
The original lens has a concave curve to it, but with a little moto tooling of the face plastic a flat panel of the lexan worked nicely.