Rad Red was a limited edition color in 04 as well as Envy Green later that year. Each came with an LE neckplate and also a black headstock.
Rad Red then made it into the regular color rotation (without the black headstock) but Envy Green did not. You can still order Rad Red new but will not get the LE designation. Some places may still have older stock in Rad Red w/ black headstock if that's what you are looking for.
Order time for the buttercream has also passed and you would need to get existing dealer stock on that as well.
The first two Ltd. colorswere Radiance Red and Envy Green. They had a black headstock and the logos were gold silk screened. The neck plate was also stamped "Limited Edition." Envy Gre is no longer available, Rad Red is but you can't order the black heastock or get the Ltd. plate unless you buy it used or NOS. The Buttercream has atching creaminlays and the words "Limited Edition 2005" stamped on the back below the neckplate and the highly discussed compensating nut. I think the ordering deadline has past for the Buttercream.