The only markings are inside the crank and there is a number 2 stamped for the right hand crank. The left hand crank has the letter "L" and the number "1" stamped inside of it. The measurements are the same as your item #
39-410, the left hand crank of which I need five (5) units. The only difference I can see is the 2-3/16" piece with the 3/8" hole is straight on my cranks and on your crank that piece has a bend in it's shape. Would that make any difference in the installation and operation of the window?