Its always tough to tell the color of something from TV footage.
How many arguments did I have over the years about the true color of the Starship Enterprise model from TOS? Some folks thought it was white or blue or green or even pink!
The way they shoot stuff for TV really affects what the colors look like on screen. Plus the fact that YOUR tv and MY tv might not be tuned the same way, so your perception of the color and mine may differ greatly.
The Vipers always looked white to me when I was a kid, but I know they weren't.
There's a great magazine/book from the 1980's about building spaceship kits. They mention that you can get a really great "live" gray color by mixing silver paint in with your white base when you airbrush. Don't know how it works, since I never did it, but that might be an interesting way to address the question.
-Gordon