Not for 2003, but hopefully some guidance where things may be similar in the versions.
In the current MS365 version, you get a waffle of the Color Theme Pallet which describes each color as an Accent Color lighter or darker with the base color at the top. If in 2003 hovering over a color does not show a name including "Accent" , "Text" or "Background" then Color Themes should not exist in that version.
If a user wanted to fix the color, the very bottom row shows basic colors not associated with the Color Theme, or choose to pick a custom color.