The Haynes manuals are generally OK, but once in a while use "generic" photos or descriptions, so you may have been looking at a Chrysler or Peugot or whatever) alternator......! Haynes is English, so you may be seeing parts used only in Europe on base models not available here.
I've seen GM heads and engine parts in the MB manual from other publishers....
No one has used external regulators for years -- the voltage regulator works better in direct contact, and it allows you to replace it (and the brushes) very easily. Bosch is usually held in by two small screws in the hole where the plug goes.
All my old Benzes have a ground strap, but that is because the alternator mount has rubber in it. I think the newer ones all mount directly to the block and have a serpentine belt.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!