Different back glass......whats the reason?

[RedPark]

I really like the Escalade rear glass... it is an easy bolt on and has a really cool 3rd break lens that stretches the whole width. I am getting one for my 04'.

 

[05Yukon23]

If it were not for the hideous plastic piece on the top I would like the grey ones better. My 05 has the one on white one and the hinge on one side gave way. I have been told (though not sure it's true) that those came on the 06s to fix the hinge problem and that you see them on other years as a replacement by GM. Can anyone confirm this?