Has anyone heard of a 68 1/2 production run?
Just because the body resembles a 69, I would not assume the car is bogus. With the 68 interior, I would not be giving up hope so fast. Lots of things happen to these bodies over the course of 40 years. In 68 the number stamped on the rad support is the produciton #, not the vin, so you cant go by that. If the fender tag had been present the produciton numbers on the tag would match the rad support.
Vin numbers would match the trans and engine if they happen to be the originals. Did you mention if you looked for that? Do you know where to look? If you find them to match I would just say that someone used a 69 dart to fix up the body.
Oh, Also, if the Dart is like the Barracuda, the door lock buttons on 68 doors are over the door handle but in 69 they are more forward on the door. Take a look at that too. I'm curious to know what you find out.