A 1992 500SL should be a KE engine management system, a 119.960. Jim's 94 coupe is an LH engine management system, a 119.970, that came out in the coupe at the start of production in 1993. The LH system followed the KE system in the 500SL, I believe at the start of the 1993 model year, and ran through 1995. In any case your engine number will tell you which you have. In other words even the system that came after yours didn't require programming. If you've got the replacement part, why not just give it a try?