Randy, I don't think the studs are 1/4-20, think they are more like 10-24 or 8-32 (probably the former?). You did not mention how you attached them, drill out (not too deep!) and tap. You can do this most of the places, but not so much on the ends (of XR7 moldings). I was able to do 2-56 on two of the three and used "Goop" on the very end one, too shallow to drill.
unfortunately the previous owner of my 70 XR7 convertible decided the best way was to drill a hole through the trim and use a self tapping screw. Lucky it is only on the end near the door and it doesn't look too bad if you use a polished stainless screw