I think what he means is the front cylinder head cover lip seal. This is common on both the 103 and 104 motors. It's the cover on the front of the cylinder head, like a "C" shaped seal where this front cover mates to the timing chain cover itself. The only problem, especially on the 104 motor is determining for sure if it's the lip seal or the front of the head gasket. The best advice I can give is to have the lip seal done, and while the valve cover is off to do this, ask them to retorque the 3 or 4 small bolts at the front of the head. They're techically considered head bolts, but they're not like the 14 or so large bolts, they're much smaller and near the front of the head. Retorquing these bolts may help cure an external 104 engine oil leak, worth a try anyways. 103 engines don't have these smaller bolts, and also 103 engines are more noted for oil mixing into the coolant when the head gasket fails, the 104 is more known for external oil leaks when the head gasket fails, usually on the right side, either up near the cylinder head front cover or on the right rear corner.