Based on that ONE photo... you can't really tell if it is a paint-over or some one has cleaned up the frame and then painted over it. Is the finish a dry semi-gloss or a tacky/oily substance? Is there any "painted over" scale build up? Do you have any more images to share? Have you crawled under the truck to examine it yourself? If not, can you have a PPI done? I have personally treated hundreds of frames for oxidation and corrosion, some customers just wanting a painted finish... that ONE image does look like work was done, but without further inspection... it's just a guess. Check the vehicle history, as previously suggested... that will give you more information upon which you can decide if to purchase.