I believe the use of the word "Sedan" refers to the placement of the compressor. Sedan mounts or brackets, even when York compressors were the standard, located the compressor above the alternator. This appears to be a preferred configuration because it leaves the alternator in the original position. When York compressors were standard there was not enough room between the alternator and hood on the 280sl. So dealer kits of the day relocated the alternator. Sanden compressors made today eliminate the piston in favor of rotary compression along the shaft. So now a "Sedan" mount can be used with a Sanden compressor, and everything else remains in a factory configuration.
To other more experienced owners: Please correct me if I'm wrong.
By the way, I have chosen to go with BudsBenz because it's easier. The kit bracket isn't a sedan style, but the Sanden compressor that comes with the kit is mounted above the alternator. And I can get the underdash blower covered to match the rest of my interior.
BudsBenz does sell the Sanden bracket and bolts as P/N: Z830-003A. I may mount mine with that yet. They manufacture the kit to order and mine's not finished yet.