I checked the back cover and it does have a 1988 date -- I think I picked this one up with a plastic folder having all of the other glove box materials usually found in a 560sl, but, alas, lacking in mine -- I have another manual (the reprint available from MB, which the dealership I bought the car from ordered for me) that is in the car, and keep the '88 at the office for reference. It did not occur to me that there was such a differnce between any of the 560sl's. I always had the impression that the 560sl was a stop gap between the 107 and 129 models -- since it seems that all of the other models were getting "modernized" around 1986.
1986 560SL (52.5k miles) sold 11/24/04
1987 560sl (55.6k miles)