Go to the Briggs website, plug in that number, and you can get the owners manual which will have your answers.
BTW, you posted 2 of 3 parts of the complete number. The 3rd, and last part has it's birthday encoded in it. Of 7 or 8 digits, the first two are year, second two are month, third two are the day, and the last ones have to do with which plant it was made in. The rest goes like this(from a Briggs book from the late 70s;
13 = displacement, in cubic inches
0 = Basic Design Series(no idea what this really means)
2 = Crankshaft orientation/Carb/Governor. 2=Horizontal shaft/ Pulsa-Jet carb/Gov, not defined
0 = Bearing type/Reduction gears/Aux drive. 0= plain bearings/no reduction/ no Aux Drive
2 = Starter type 2= rewind starter
The second part of the number is the "type", and has to do with more specific differences of construction, a list that I don't have.