Dead on Dave. It is not a smoker at all, basically a wooden oven that uses charcoal. Kinda like a wooden dutch oven, same principal, coals on top to cook the food, with the metal lining reflecting the heat all around the meat, that's how it roasts.
If you want a pig roaster that will add smoke, make one out of cinder blocks, rebar, and heavy grating. Set up you blocks about 3-4 high, leaving one end open to shovel in the coals and wood, place rebar across the top for support, and then the grating over that for your split hog to lay on. After it's ready and the hog in on, cover with heavy cardboard to keep the smoke in. I forgot the guy's name, but he's famous for doing hogs this way, had a documentary made about him, and he even won the prestigious James Beard Award. From GA or AL i believe.