I agree with achipmunk. I did not take my leafs apart, and as I use my truck for hauling, there is always rust etc. coming out from the leaves. Makes sense though, as they are always flexing.
If I had lots of time and money, I'd go with the take apart and poly liner route. Even so, if you haul, a flexible paint, like rustoleum might be the ticket.
If, like me you paint your leaves together, I'd use matt, or flat black for them. Then a little wirebrushing, and you are ready for touch up-often.
