It's safest just to lay some black base down, but if you are satisfied with the condition, clearing them might be okay. It's likely that you would see some flaws in bright sunlight if you did it that way, though. Depends on what you are looking for. We can't afford redos, so in our shop they would get a coat of black epoxy sealer, a coat of black base, and clear. This will always produce a guaranteed result.