Well, there are no older Mossbergs left in the US. Nope, all gone. All of 'em.
OK- I will admit I DO collect Mossy's
Just for grins, check thru the on-line auctions, under Higgins. There are a lot of guns made for Sears that sell for pennies instead of dollars. Originally made by Savage, Marlin, Winchester, Mossberg.
After working thru those, check Revelation (Western Auto brand) and Western Field (Montgomery Ward brand)