I've noticed that the rear window on a lot of the 06 1500 models aren't tinted. Why?

 

my '05 is the same way........... I think it has to do with the auto dimming rearview mirror.
I plan on tinting it eventually

 

My 05 quad cab came with the rear tinted windows and I have auto dimming mirror.

 

It has to do with the options on the check sheet. Mine came with a solid non-tinted window. Fixed that really fast with some Solar-Gard tint from my local shop.

 

It has to do with the options packages, not the rear-view. I've got the auto-dimmer and tinted rear glass. It's usually part of "comfort packages" labeled as "privacy glass" on most vehicles. I don't know what it is specifically called on DCX vehicles.