I'm not going to loot my documentation for details right now, assuming it even tells you what kind of compressor it is like e.g. MBZ documentation does. My W126 manual tells the manufacturer and part number of AC compressors, turbochargers, etc. Like Audi, they usually specify an internal part number for fluids and leave you to figure out the spec from it if you want to use anything other than their magical juice. But if you look up the compressor on the manufacturer's page, it will tell you what viscosity of oil to use.