While I imagine a clearcoat or varnish is used sometimes, historically plain colours were not clearcoated.
One specialist told me that for a vintage three wheeler that should be brushed, he would still spray as a lot of restorers would, but the final finish would be a brushed clearcoat. He maintained that doing that, you got the look of immaculate brushwork, and the advantage of spray paint, namely a quick drying finish. The correct finish, brushed coach-paint takes a long time to dry. And is seriously hard work to get a good result.
