Sounds like we're arguing semantics here. All cars produced by BMW that had the lighterweight monocoques should be categorized CSLs. I think that's the least common denominator, although I've never seen anyone measure exactly how thin the main steel panels (i.e., the roof) are on a CSL vs. a non-CSL. Virtually every other component of the car could be reproduced or faked, but I can't imagine any way you'd get a complete body made of the thinner gauge steel.
Whether or not cars (such as my beloved # 227 5396) that have city packs, are true lightweights depends. They're authentic CSLs, but they're clearly not as "leicht" as models which have plastic windows, and aluminum doors. There is one other interesting point though. No one would dare say that the Bat cars were not genuine lightweights, but they had steel decklids and an additional 30-50 pounds worth of induced drag added to them (front airdam, wingsplits, roof hoop, rear wing) so theoretically they're not as light as other model variants.
I suppose your definition of what makes a CSL "lightweight" depends on your perspective, but for my part, if the car had a VIN which falls in line with what the factory claimed, it's at least a genuine CSL, and we know how many there were made. They are, if not lightweight, certainly rare.