I was probably in A&F when that gun was on the shelf. At that time, a Knockabout 20 sold for $425, an astronomical price for such a gun. They were not flying off the shelves. There were rows of Knockabouts on the rack from 12 to .410. A sideplated boxlock at $675 was a bit steep also.
My 1936 A&F catalog shows a Knockabout with ejectors at $175, a 20E at $275. They were never cheap guns, for sure. When you consider that A&F offered the Parker DHE at $186.50 in the same catalog, the Fox CE at $117, the Elsie Specialty at $118.50, and the Ithaca NID 4E at $130, it gives you an interesting basis for comparison.