Honda Engines Europe EEC
try here. It will give you a parts list that might show you where they go.
If its a honda gcv then usually its (in order of engine out to carb cover.)
gasket, black spacer, gasket, metal shield, gasket,carb, gasket, gov control bracket, gasket, air filter cover.
Can be frustrating.
You could look at the rear of the deck and find the model of the mower, but if those labels are gone, there should still be a model and serial number stamped on the engine block.