Thanks very much 71Beige280SL and shvegel. Actually, the cut-a-way through the sill showing the jack supports is the biggest help to me. Looking at an exploded diagram on a Bud's Benz site, I see a Frame Rail, Frame Rail Cap and Rocker Panel Cover. I gather your photo is end view of the Rail and Cap in position? The photo is a big help. It looks as though there is a paenl beneatht the lower trim piece that unscrews (and I have that feedback from the forum). I am going to remove that piece soon and hopefully that will answer a bunch of my questions. In the meantime, the additional photos that you offer would be much appreciated.
Thank you again,
Harry