Parker Bros. did all sorts of weird and wonderful stuff to meet customer's wishes. I have an 1889 vintage, 2-frame, GH-Grade, Damascus barrel 12-gauge that weighs a fraction of an ounce over nine pounds. The barrels are very straight and thick with a weight stamp of 5 8. My Grandfather's 1890-vintage, 3-frame, PH-Grade, Twist barrel, 30-inch, cylinder bore, 12-gauge, has barrels that swamp in very fast, and it only weighs 8 pounds 8 ounces?!? While my gun is rather muzzle heavy, Grandpa's is muzzle light with much of the weight between your hands. I kind of suspect the original purchaser of Grandpa's gun got it to shoot pumpkin balls.
Of course our all time favorite "heavy twelve" is the 6-frame, VH-Grade, the late Jack Puglisi had for sale some years ago --