It is best to match them up to a sign or decal but, it's also real nice to have a bit of a reference.
For Gilmore I have Ditzler/PPG color codes: Cream = 80463 Red = 70328
These are something I came across years ago. I don't know the accuracy of the color. It seems people are hesitant to provide color numbers around here. Use them at your own risk. The numbers are in the yellow and red family.