I think Bruce's post wasn't about the artistic aspect of it. I think he was calling "BS" on it because the paper would not let enough light through. Dash bulbs aren't the brightest, and placing something that's generally considered opaque between them and your eyes isn't a good thing. And the "idiot light" icons are already colored (The alert icons and coloration are likely ISO standards) - so adding a different color is going to make it worse. So I'm also calling BS on it being real.
Now... using tinted films - that would work. Or, go to the local hobby shop and buy Tamiya transparent acrylic paint. They come in a variety of colors. It's like the candy top coat for automotive paint, but for models. Back in the '80s, I used the clear red to recolor the tail lamps on my old Mercedes. The plastic had faded badly after 30 years. I couldn't afford replacement parts (which amazingly were still available!).