I had the tanks on my 74 KX450 painted 4 years ago (they are also plastic)
If you want a "show" piece, its ok, if you want to actually ride the bike plan on the paint peeling off sooner or later. Dupont made a product that the local paint shop used (remember the Monte Carlo, El Camino SS's, had a plastic front end on them, same product). My tanks now are half peeled off from falling over in the trailer, to the occasional "race induced" :confused:
scratches. My 2c worth.