All:
Rather than look for those "factory" options as an add-on option, see if there is the replacement part available instead. This may in the SSR's case require "borrowing" the VIN of an SSR with the tonneau cover carpeted - simply tell the parts man, "The tonneau cover was damaged, I've salvaged what I can, but I need some parts." if he asks for a VIN, give him the borrowed VIN - the option list should come up on the computer with the part numbers you need. Feel free to ask for a printout of the blowup diagram on his computer screen if you want - it's not a national secret. You can relax - there is no owner's cross reference in the parts system, and as far as the parts guy knows you might simply work for a body shop that's gathering the parts to "fix" the alleged damaged tonneau.
There absolutely has to be replacement parts available, albeit they may not be in the system yet, and worse yet some of the parts guys may not even know about the SSR. (Having practically grown up in a GM dealership's parts department, I know some of the parts guys don't get out from behind the counter much.) Be patient, and don't be afraid to try a few dealerships.
My father was a parts manager for years in a small Western Kansas Chevy dealership. You'd be surprised what's still in the parts system. For example, in 1986 we found a complete NOS grille for a 1956 Chevy (was quickly purchased and installed on my Dad's '56) and when I was building my '55 3100 short box, on a lark I looked for the front turn signals and they were still in there - had them shipped from Denver SPO the next day.
My dad and I were laughing about the SSR's door locks - you know, the old fashoned chromed plastic lock knobs. GM hasn't used those since the early eighties, and here they are again. Somewhere at GM a warehouse manager is saying "Crap, we gotta keep carrying these things in the system for another thirty years?":lol
