If you want to know what's under the hood of a Benz, usually you can just look at the trunk. MB has a history of making several versions of a car with one body style. They may look alike, but they oftem perform quite differently.
Until the late eighties, the emblems started with a number. That's usually an indication of the engine displacement in liters, but it's really the model number of the car. The letters that follow tell you more. The S means Super, I guess because it was the biggest body style, and the E means Einspritzung for fuel injection. An L means Lang for the long-wheelbase sedan, it means you got an extra six inches of legroom in the back seat. D means Diesel, T means Transport or station wagon.
Sometimes you see another emblems on the right side. Sometimes underneath the other emblem. This provides further information about some special feature, such as 4-MATIC, for the station wagon for four wheel drive, or TURBODIESEL, or someting like 2.6,3.5,4.5, or 6.3, which denotes a higher or lower engine displacement than the standard offering.
It's actually really confusing and fascinating in a strange, German way, but once learned, you can tell all sorts of things about almost any Mercedes Benz just by looking at the trunk emblems.