Use a very thin metal sealer... not really primer and use the laquer paint... that will be very thin and what I did.... you can easily see all the marks in the metal.
I used House of Kolor epoxy on mine, same as the car. I put two good coats on it, no sanding (obviously) then shot Omni satin black over it. I would never paint anything without primer, period.
the sealer is a 'primer' but not a bulk building paint... its not 'sandable'. I hope I have explained it well, but what you suggest is a good idea as well.