Early 4423’s were dull aluminum with the bluey green panel on the tank. Later ones were all blue.
13385 is not a good serial number for the 4423 Sportwin motors but it is for the 4425 Sportsman motors.
4425-13385 would be a 1949 model.
A 4423 Sportwin with the gas gauge on the front of the tank.
The smaller 4425 Sportsman without the gas gauge.
