The difference b/n the GTS package and Swinger

GTS details at http://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1969/69_Dart0006.jpg

Swinger details at http://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1969/69_Dart0008.jpg

(For the best quality, copy & paste the actual page link like I do)