I've never heard of this, is it true?
"unique rear passenger compartment fresh air ducting exclusive to early-production models."
Absolutely not.
The rear seat ducting which went under the carpet along the hump and under the seats
to dump out on either side of the hump was introduced on the E3 3.0S
and was somewhat more common on the E3 3.0Si. Both models
later production than an early lightweight E9 CSL by at least a year.
Still, of all the Bavarias I went through in the 80's and 90's (a LOT)
I only saw it factory installed one time on an Si.
I have never seen it on a coupe, let alone any L, certainly not a early lightweight.
If it is on this car it was added over the years. But....WHY??!?!!?
It'd be an interesting feature on an E3 where one might actually have passengers in back.
But a homologation lightweight CSL? "I don't think so Tim."
What rubbish to call this "exclusive to early" CSLs!