IMO... GM has no quality or worksmanship problem putting the stripes on. If there were then they would not be offered at all.
The issue seems to have started with the perception of potential increased and unacceptable production delays on the front of the car and a follow on decision making process that was and is incomplete. At the rear of the car the problem is the stripe termination points on both of the rear accessory air dams currently planned for production as accessories.
It is what it is- for now