Typically the instrument faces (or dials) were the pale-green color they were painted with Radium to "glow", but not all instruments were painted with Radium.
e.g.The Elgin 37500 never contained Radium or glowed.
http://www.aviation-dream.com/images..._de%20bord.jpg
Anything painted on the instrument panel or decals could be any color.
