michael,
i'd think that would be according to your own personal taste & what your trying to achieve. if you're going for pure restoration i'd just sand & paint. i'm mostly familiar with AD trucks & i know very little if any attempt was made at the factory to hide any spot welds any where on the truck. i'm not a purist restorer but i had a friend who was & he told me that too much smoothing can lose you points for what is called "over restoration". if your tailgate is bare metal you'll need to sand with at least 80 grit & once primed you'll see the spot welds won't be nearly as noticeable.
robert
