This Liberty Single has a magneto in the flywheel and in one pic you can see the cover has been moved aside so there is access to the points for adjustment.

The serial number is most often found on the side of the transom clamp under the exhaust. These numbers are often very difficult to see because they were stamped on, sometimes without much enthusiasm.

If the number isn't here look on the exhaust manifold.
Every once on awhile you'll find it elsewhere on the transom clamp.