The early "E1" box has no model picture to the side flaps. These might still be found with an brown "Striker" side ( 1964 ), all later printings are having two blue sides. Some models having white circles showing the models funtion on the side flaps, that's not sub-variation for me. That circle is there ( if the model has some sort of function ) ot not, there's not a single one which exist with both types.