Hmmmmmmm never thought about it as I have always called it the Dart "GTS". But looking at all of the tail stripes should I really be calling it the Dart GT Sport? But my '69 Dart is a stripe delete and does have a front fender callout GTS, so confusing. GTS is so much easier to say
Interesting thing is that, nowhere on a 69 GTS is there a emblem or marking of the word DART.
But my '69 Dart is a stripe delete and does have a front fender callout 
