Hi Julian, the engine is an 11 cubic inch (about 184 cc) side valve Briggs and Stratton engine of the first design generation, with a vertical crankshaft, a Pulsa-Jet carburetor, and a vertical-pull starter. I can't tell you when it was made because I think there is an error in the Code you posted (the last block of numbers). Without the correct Code I also can't tell you what kind of ignition it has.

Here is the Illustrated Parts List:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6lnsHVJ1DajI.pdf

Here is the Operator's Manual:
http://bsintek.basco.com/BriggsDocumentDisplay/msowGK-K_ny7tH217FzoPu.pdf

Engines of that generation are sometimes overhauled if they do not need much in the way of new parts. They are not valuable, overhauled or not, and only someone with a sentimental attachment to one would spend a lot of time or money on it. Nevertheless it is often possible to get them running well for very little cost, and they can be very satisfactory mower engines.