Never mind, 'cuz ...
... I've already been to Cleveland and am now back home again. I did drive by the address I mentioned: found a plant there, but I couldn't find any evidence whatsoever of Premier's existence there. I DID, however, find an old (and apparently long-closed) GE plant at the corner of Ivanhoe and Mandalay: would anyone know if that had anything to do with the pre- or post-70's GE floorcare line?