Captain: yes, mine is leaking from there - but my engine is also a yachtwin 6hp. So is that bad ?
Not really bad but one of the features of the Yachtwin is that the normal exhaust outlet is plugged so that exhaust gases exit via the outlets in the special 5" extension ( see where the pencil points in the picture below) so that when going astern you don't draw them into the prop and loose reverse thrust.
But there is a small drain tube which you can just see in the picture in #2, tucked in the corner by the water intake. It's shown on the parts diagrams along with the plug for the exhaust outlet. Maybe that's where the oil is coming from.
Whatever unburnt oil from the fuel leaking from around the lower unit is normal for a two stroke.
See the item on the Engine FAQs board about "Oil leaking around the lower unit"
You only have to worry if you find gear oil leaking or signs of water intrusion into the gearcase.