The 67 did not have chrome tips. When I put on a stock 340 exhaust system from year one on my 67 last year I found that out. The 68 tips were a little short, because apparently, I was told a 67 dart is a few inches longer than the 68-69. There are repos to fit the 67 but they are longer and smaller in diameter. Check this Year One link it may help you:
http://www.yearone.com/serverfiles/fbshopmain2.asp?input=1967+Dart+GTS&SM=1&SC=1
By the way that is a nice GTS you are looking at, good luck!