1972 Dodge DW Pickup Back Glass

The window is gorgeous and I can't wait to get it installed. The problem is I can't find the correct gasket for the installation. I have just purchased my fourth gasket and will try again tomorrow. I'm paying an exorbitant amount of shipping charges because I am trying to get my truck finished. Might have to drive it home without a rear window. 1973 D300 Custom Pickup. The slider is the exact same size as the original window that came out of the pickup. I have purchased the gasket that CR Laurence says is needed for my pickup. It didn't work. The original glass seems to be a little thicker, but the dimensions are same. I have almost $500 in gaskets including shipping and nothing is working. The original glass had a locker strip and it was not a slider.