I just called the Koga dealer; he asked the manufacturer. Those decals are ... "wet type". To be soaked in luke warm water. (Not sure about how long they should swimm, though...)
Obviously, these decals need a protective layer of clear coat. I read some horror stories about decals that melted when sprayed with the wrong type of clear coat. Could someone point me to any suitable clear coat brand names? I would really appreciate the experts imput.