Fastback reverse light wiring

Hello FABO!
Using an American autowire kit. Anyone know if i remove the nipple from the back of the housing ? The one they send looks like the male tongs would be much larger. If i am supposed to.... how does it come off. I've tried penetrating oil and can get it spin but even with a flat headed persuasion it doesn't wanna budge. 16318371485931017913549.jpg