Call Sportsmobile and ask if they can tell you how they might've done things in 1986. There are employees at each of the 3 locations that have been there that long.
Nancy at SMB North in Indiana has been there since the dawn of the pop top I think.
Paul? I think, at the Texas location has as well.
Not sure about West unless you could get the owners.
But......On all newer SMBs there is a fuse panel in a cabinet, under couch, or somewhere in the 'house' cabinetry for all the house circuits.
I've done what you did and worse. It'll buff out.