Seat belts
Sean,
Congrats to your CSL!
I think it's fully possible, but rare, to find a 1972/73 CSL where the seat belts were never mounted. It also depends on the market. For some countries and year models, it was mandatory with seat belts.
Looking into the original CSL sales brochures from 1972 (spring and September 1972), it says that 2- and 3-point seat belts were prepared for all four seats (Anschraubplatten).
In the CSL owner's manuals from February and November 1972 nothing is mentioned about seat belts. The same for the CSL owner's manual from 1973.
But these CSL manuals are only a supplement to the more detailed E9 manual (red version). In the E9 manual, it says that the seat belts are prepared and your dealer is ready to install them upon request.
However, as from 1974 I think 3-point seat belts in the front were standard from factory and 2-point in the rear was an option BMW charged for.
There are a lot of variations. For instance, the Swedish CSLs sold 1974-1975 had the front "Klippan" seat belts mounted in the roof:
http://www.bmwmregistry.com/detail.php?id=4197 (third picture)
Cheers
Henric
ps. please also see the private message I have sent to you