You know Im not to sure which one your reffering to but there arent many dart kits out there....the one I can remember off hand is a 68 Dart by AMT which I think was called Mr. Norms Dart
Revell also had one I believe a 68 or 69 Dodge Dart GTS....the "Norms" dart can still be found....The Revell kit is a lil harder to find but not un-common. I got my Dart GTS from Ebay though....Hope this helps and Im sure that others will be able to either correct or add on to the info Ive given.
Good Luck,
Chris