1967 Dart Convertible Trunk Spring Support
There is really no way for me to personally confirm this, but I believe the trunk torsion bar supports were different for 67 compared to 68. Because my 67 dart had this problem and thought it was odd, my old man has never seen this issue come across the shop floor when he worked at a dodge dealership. And seeing that your 67 is having a similar issue, may show they had a production/quality issue with the support stampings or the design itself in 67.
Two cars out of how many were produced is by no means statistically significant, but does get one thinking.