Is this correct for swapping Master Cylinder from single to dual?

I am not getting anywhere with my research on this topic. in my 66 dart, swapping to disc front, keeping rear drums (9in). When I bought the new Master Cyl Dorman M80266, and I removed the original MC and I reused the original Push rod. I simply pulled it out. However I also have the original spring and booty that can not be properly installed onto the new MC. See my pic of what I have done and let me know if I am supposed to still use this spring, or is it not needed with this new MC. You can see the thing on the ground is what is supposed to hold the spring from the old MC. IMG_3700 2.jpg