yup it is normal as long as it is burned up black oil (not new oil) you are seeing. 2 strokers are designed to burn their oil and any extra goes out the exhaust. If it is fresh oil that is NOT normal and you need to dig further to confirm the source.
on the old 2 stokers you might consider premixing your oil and fuel if you're not already. Usually go about 50:1 gas to oil ratio. Disconnect any automatic oiling system. At least then you know the motor is getting lubed whenever it is running.