It is correct, it is Machine Doubling. But that trips up a lot of collectors for the longest time. On a doubled die, other than notches, you look at the centers of the design to find a doubled die. Look for the spread. If you looking on the outside edges of the devices you are setting your self up for a fall. Look for the devices to be enlarged.
Different forms of Machine Doubling. (note how it always affects the outsides of the devices: