I grind the weld, paint all the parts and bolt them together, making all the checks to make sure the tail gate will fit right and then scrape the paint at the weld and tack weld the spots with my wire welder. Then use low pressure to touch-up the welds. Or you could use a small brush. The spots are in an area that isn't noticable anyway. You do need these welds or the bed sides will slip and get wider at the top. Hope this helps.

Truck Tinker