I would have to look at that stuff to me certain but I think the 230 is likely a 230 which was twin carb single barrel barbs. The230S had twin two barrel carbs but I believe both were vacuum advance distrbutors.
The reason the numbers are similar is because both units are vacuum advance but have different advance curves. Early 230SL distributors have a very fast curve and are also very hard to set up. Next to duel point they're one of the hardest to do.
The 230S may have two curves which is fairly common on later units. In this case they use two different sizes of flyweights, one for up to 3,000 RPM and then the second would start about 4,500 RPM and go to about 5,000 RPM. The extra high end advance would give another 5 - 10 degrees of advance. Early 450SL's have this feature.
