Gasboy,
Shell red is mostly the same over time.
However, they have had at least three yellows. In addition to Rich's numbers check these out for pre 1950 stuff.
PPG# 81652 Fleet Yellow
PPG# 71660 Fleet Red
Sikkens Solid #418A1 Tan
If your friend is using a decal he may want to have the paint matched to the decal.
Ed