Before you give up on retouch, spend $10 for some 1000 grit sandpaper and model paint in white and gray. Use the sandpaper with some water to remove the primer- take your time and just remove the primer, not the underlying paint. Chances are that MOST of what lies under that primer is good original white paint. If the sandpaper is too much after a while, go to automotive polishing (not rubbing) compound to get the rest of it off. Then if you're lucky you can just touch up the white areas with the model paint and use the gray as necessary to duplicate the splatter effect. Worth a try.