There was a interesting article in the MBCA Star magazine about new oils and older engines. The gist of the article is that if the oil is appropriate for 2005 or newer vehicles it may not have the additives necessary for an older engine. I have a PDF from George Murphy Technical Director with MBCA. If you want to know what MB approves for fluids I'll send it to you.
Happy Benzing
Darryl, Hill
350 SL4.5 #60
1967 250sl "California"