When I went to replace my soft top, the new top, had two flaps of canvas to hold the "floating" rod, 6" back from the windshield, that rivets to the canvas strap connecting the front middle and rear bows. There were holes in the canvas from previous rivets. The previous owner had apparently ditched that rod and used a soft top designed for a earlier 113 which didn't use this rod. One of my books said these rods were added to limit wind buffetting of the top at speed. My inquires told me the part was not available. After inspecting another 1969 113 and taking measurements, I was able to buy some brake line from and autoparts store of the correct dimension, cut it down to the correct length, drilled holes in the ends and riveted it to the canvas straps, through the original holes, and then glued the canvas flaps to it. It looks factory and hasn't caused any problems.
1969 280SL, manual, MB TEX, green/cognac