You’ll have to look harder, it’s there. The housing which has the starter rope is called the shroud which wraps around the engine to help cooling. The area of the shroud above the spark plug is where Briggs would stamp in the model, type and code numbers, and it would take a lot of wear on those older units to wear them off. Some of the older ones had it on the shroud side, opposite the carb. Get one of the better half’s old scrubbies from the kitchen sink and some Windex. Dampen the scrubby with the Windex and start cleaning this area. If the scrubby get full of crap, rinse it clean and start again.