Not sure this will helps, but Boba maker lists his ESB paint list in this thread, hope he doens't mknd me posting it here.
Personally when I paint my scratch build I'll be mixing the paints myself as long as I can find some screen caps of the ROTJ helmet in natural light I'll be able to match the colours quite closely this way. If you want to go the spray can route, Tamiya colours might be the best route to go, as they have a wide range that seem to come quite close to the oiginal colours, but you could always mist ove the colours that don't match quite close enough with a brighter or darker colour to either lighten or darken the tone. Also don't forget washes will tone down some colours too when weathering them. Hope this helps a bit.