The vinyl decals are definitely individual letters applied over the painted panels. I know because I sourced everything myself and specced out the paint job.
The clearcoat was *not* applied over the decals. These are vinyl decals on top of clearcoat. The reason why we did that is because the "United States of America" yellow bands are original decals and they did not pass the "melt test" of applying clearcoat over top. Therefore we applied all the decals on top of the clear.
One thing I may do is "test" the removal of these decals by trying to carefully remove one of the Columbus tubing decals. Which were also sourced from velocals and applied at the same time. One corner never adhered properly anyways.
I think chances are very good that a heat gun would lift the decal no problem and that naptha would clean up the adhesive residue. There seems to be a small chance that the decal adhered to the clearcoat.
Yes, I sunk $600 into the repaint and replacement decals. In retrospect I wished I would have applied the decals myself. Humans make errors.