The thing is, all the macbook pro's where i work (Currys, an electrical reseller) are not lighter at the bottom, or at least no where near as much! And they all had the 9CA4 (Samsung screens) oppose to my 9CA3 (LG-Phillips screen)
Do you know what i think it is... the top two 3rds of the 9ca3 screens are the LG part and the bottom 3rd is the Phillips part hahahathough i will give phillips there due as i have an iPod dock that is made by phillips and it is very good in every way...
I've had many Macbook Pros. In fact I basically change with every update. I've had yellowish screens, white blotches, dust, dead and stuck pixels, flickering. This 9CA4 screen may be the best screen I've ever had in a MacBook Pro.