I just found this link for safelite auto glass, and put in the year make and model of your Dart, and they have the rear glass, and I do believe it is nation wide, BUT the glass for the rear window is goung to cost a whopping $905.00 plus a 6% christmas discount to bring it down to 844.99 not including tax.
The front glass would be $493.68 and with the season discount at 61% it drops it down to $189.05 not including tax. It also goes on to say you may need additional parts of 102.36 for the rubber seal. Keep in mind I had to use my zip code for location so yours may be different.
I would call around to some local shops in your area for your rear window, like I did with my front windsheild on my Dart it cost about $280.00 with seal from a place out here called Discount Auto Glass, I guess there is not much difference in price for the front glass and seal.
Hope this helps
I really appreciate you looking into this for me. I knew that rear window was going to be a small fortune... damn. I am going to do some calling around and see what I can come up with. Appreciate all the help guys.
Just to give you a heads-up, I worked for Safelite for a loong time, they can get the windshield (I got one for a friend's 69 cuda) but not the back glass. It'll say they can online but it's unavailable. We got all that old stuff from Pilkington Classics (formerly PPG). The moldings are also unavailable, like the gaskets if it's gasket set, from Safelite though they'll tell you they can order them. Best place to look for anything would be Auto City Classics http://www.autocityclassic.com/Scripts/default.asp, they set up at all the shows (like Mopars Carlisle), are reasonable, and have lots of hard-to-find parts. And if you're not installing it yourself and you go with somewhere like Safelite or Diamond, make sure you take the car to the shop and do NOT opt for mobile service (trust me on this one!!!!)