Need a few more numbers. The 583 tells me it was made by either High Standard or Harrington and Richardson. The part of the Sears number following the decimal point will probably identify which model it is. But, we really only need to know if it is a single shot, double barrel, pump, bolt action, or semi-automatic to put a price on any Sears branded gun. Or, you can go to Walmart or any sporting goods store and find the price on a new utility grade shotgun with the same action type in the same gauge. Then you can figure your used gun is worth between 1/2 and 3/4 as much, depending on condition.