I made some door emblems for another Fabo member for his 68.
I made the mounting studs much larger in diameter with tapped holes in the center.
I then used 83 deg ( iirc rather than 100 deg) short flat head screws and counter sunk some fender washers.
It worked well.
As for the 67. Depending on how much material is left on the mounting studs you might be able to drill out the centers and tap for #4 or smaller screws.
Or maybe tap the outside and use a thin nut on the outside.
Regardless they need to be basically flush with the door card as they fit pretty much right up against the door frame.