You can use automotive paints on plastic models as so long as you seal the plastic properly. Use a good primer. I myself first use a light coat of Krylon primer. Krylon is an excellent barrier between the plastic and any type of paint. Then I use two light coats of Testors white primer. You can also use a can of flat white paint if that is not readily available. This will be a neutral base color for any other paints you choose to use.