The originals were painted a light gray, but darker then the insignia white color that I use.
The red stripes were also alittle darker red then how they looked on screen...(which ended up like a dark orange on screen)
For the Monogram/Revell 1/32 scale kits, if you want to paint them like the original models, I suggest a light sea gray, or light battleship gray.
Again though..... they won't look like they did on screen.