Dear Erie,
On close examination of the photo I noticed that there seems to be a bit of whitening around the perimeter of the decals. I wonder if you used a decal setting solution to make sure the decals rests fully against the body and contours, including the rivets? Make sure you use a setting fluid that is recommended by your decal manufacturer, and then apply a puddle over the decal. Use a straight pin to pierce the decal where you see pockets of air, and pierce the decal to allow the fluid to get underneath. The solution should soften the decal sufficiently that it will wrap itself around rivets and such and also become transparent to where the decal edges are hard to detect. Only after you are satisfied with the decals should you attempt to cover with Dullcoat.
-Ed