No. That pic is actually from an '86 M103, so apparently MB did a flip flop on this design. I suppose the thermovalve was in an unknown location from '86-'87? Then model years '88-'89 put it on the head.... then they went back to original design for the last three years: '90-'92.
Again, if someone/anyone has a '90-'92 300E, and doesn't mind taking 5 minutes to remove your air filter assy and checking this connection for me, I'd truly appreciate it.