Your memory is the same as mine!
I also have a copy of the 'Chevrolet Special Equipment' book - that I was referring to - I copied from the green sheets a friend of mine loaned me in the '70's (Robert Christianson, who also ran a '69 in Trans-Am and later and later a 73 Camaro in IMSA-GT). My knowledge of the 'service duty' rear mostly goes to information I got from him, and later I purchased one of the rears that was used in his '69 Z28 TA car.
The reason I asked you those questions is because you are knowledgeable, and I was hoping that you could clear up some of the misinformation that is out there. The 'few lines' in the available books dedicated to the service package rear do not do justice to the differences in that rear end, and seems to be mostly 'speculation' dreamed up by the authors...
Thanks for your informative response to my questions, and I for one would love to know more about the differences between JL8 and Service Package rears.
PS. I also do not believe one could order a new Camaro for the street and have the factory install a service package rear end, although it's certainly possible (for a few months) to order the JL8 rear and then pay the almost $1000 for the service package (OTC) and pay the dealer to install it.. although that scenario certainly makes no sense! As I understand it, the service package rears were difficult to get and likely required someone 'close to Chevrolet' to get one promptly for a TA car. Bob told me he had a relationship with Vince Piggins when he was running that assisted him in getting some of the special parts.