This is also mentioned in John Hoopers book The 1969 Camaro reference book, along with how many were sold( 8271 yellow, vs 2359 blue). The yellow also had a different option number of RPO U69, and the blue was RPO U79. It might be a handy book to have in your library.
John Hoopers book covers some different aspects than Jerrys, I wouldn't say one is better than the other, most of the info is similar of coarse, but Hoopers book has some neat little tid bits, like the RS option added almost 30lbs to the curb weight of the car along with many other interesting options and facts. You may find it a good read as well.