[Kevin Kuehn]

There are various setting solutions that model builders use to brush over the decal after it's been first set. The solution softens the film, allowing the decal film to pull down tight against any surface irregularities when it dries, which eliminates voids under the film that show up as white spots when the film dries. Hiding the film edges becomes a process of applying many coats of clear finish over the area - enough so that the edges can be feather sanded in. There are various
thicknesses of decal films available too. However the thinner ones will be much more fragile to apply. I use to use this stuff back when I was into model railroading when I was younger. It was really amazing how many irregularities you cold conform a decal over.

I think during manufacturing that they used the silk screening process. There's no way they could have taken the time to apply individual decals, unless it was for a prototype.