Thanks for the replies, all. A real quandry now. Our sofa was in the curb-side slide. We moved it months ago to the street-side slide. All of the bolts and fastening hardware were removed, and put in a one quart plastic storage bag, labeled and put away. The sofa is not fastened down as it is now. There are no holes beneath the slide on the street-side. I guess this will remain one of life's little mysteries.