Let's not turn this into a testosterone contest, ok boys? Please.
Chicane, BMW routinely substitutes parts that will work for parts that they're unwilling to mass produce. For instance, if you look up the exhaust manifold for 2002ti or 1600ti, the correct part is illustrated, but the p/n is for a run-of-the-mill manifold.
Regarding the CSL roof, I just went though BMW MT's material -- in their green coupe book and reproduced CSL brochure -- on the CSL and all of the usual lightening measures are listed, but the roof is not mentioned. On the other hand, I've heard enough CSL owners complain about their easily dented roofs that there may be something to it. Also, the word out there is that sunroofs are never found in CSLs because the roof skin isn't compatible with it. Or... it just may be that you wouldn't add the weight at the top of a car that had an "L" in it's name.
Anyway, Matt McGinn has a CSL in his shop at the moment that he's restoring. I'll ask him to have a look at it.