I built one of the original Empire kits way back when but never got around to painting it, I have one of the newer kit's waiting to be built.
Your best bet for reference would be Studio Scale forums like RPF, Modelers Magic has a couple, Starship Modeler, there are others but unfortunately many have become MEMBERS ONLY forums and can't be viewed any more.
Do a search and you should be able to turn up pictures from exhibits that people have taken, some are very detailed close ups.
If you are going authentic paint than you will need to get Floquil, that's what ILM used.
I have some paints (mixed brands) jotted down, info I got off RPF.
Main Fuselage Testors MM IJA Grey (Greenish Grey)
Also 50/50 IJA Grey and MM Camouflage Grey
On the Skirt Flat Gull Grey
Box Car Red (Floquil) or Polly Scale Mineral Red, Red w/ camo grey and a little white for the pink.
Dark Green areas Polly Scale German Uniform Grey or Vallejo Field Grey.
Rear hull mainly Gull Grey
Details in MM Neutral Grey, Flat Black, Dark Gull Grey and Field / German Uniform Grey.
I think there is also some yellow and rust.
E...