Casey Morgan said he spied the wallet buried in attic insulation.
It appears the wallet fell from Hamp's pocket and tumbled between roofing boards into the attic, where it rested for more than four decades.
Morgan's boss, Terry Thelen, later tracked down Hamp's name through an Alma telephone book and reached his son.
Now 78, Hamp said, "We got back all of the pictures, and several of the bills in it were silver certificates." The wallet also held other papers and $23 in currency.