Here' s another thing.....
Go here.....
http://www.e-gunparts.com/crossref.asp which is a cross reference sheet. Scroll down to the Western Auto shotguns and find your specfic model and who it was made by, i.e, Marlin, Springfield, Hight-Standard, Savage, etc... and the matching model number. That will cut your chase by 90%. Once you find the manafactures model number then look for that part. The same page I gave you above has a great many products for the older model guns. You can also check here....
http://www.brownells.com
http://www.gunbroker.com or other gun auction sights.
Good luck to you.