Yes, skins and style sheets would be the best route.
You should probably set a folder on the project for styles and put those items in there and then call the style from the main application file.
Then of course, you will have to make sure nobody did any style changes in the components themselves or through code.
how to create a theme swc in flex ? and will these swc override global css and inline styles?
Is there any way to override inline and Extenal css using theme swc?
I haven't tried it, but I believe Skins prevent most styling overrides.
But, they still have to setup the Skin in the application.