The head gasket "set" may contain more parts than you need. If I recall correctly it contains: head gasket, intake manifold gasket, exhaust manifold gaskets, front cover "U" seal, radial seal (on front cover), valve cover gasket, EGR gasket.
You can run down to your local MB dealer and ask to look at one to make sure. I didn't need all these parts (valve cover gasket, U seal, radial seal) so I just bought the parts individually.
You will absolutely need the head gasket
, intake and exhaust manifold gaskets, EGR valve gasket (most likely), and the U seal if you've never taken off the front cover. The radial seal is most likely still good, but you never know.
Also having your head cleaned/refurbed at a machine shop is money well spent. Pictures tell the story....
'91 300E, 215K miles