Who made my Sears 20 gauge shotgun?

My grandfather used to shoot competitively and before he passed away he handed down his old 20 gauge Sears shotgun to me. According to family he got the gun from Sears in the mid 60s to mid 70s. I'd like to know if anyone knows who manufactured Sears' shotguns around that time frame. (By the way I took it out last weekend and it is in perfect working order, bit nerve racking being the first person to shoot it in 20 years.)