That's a great looking tail light and in good shape, good price. I like it much better than the plain one lens acorn types, you got lucky there! You also got lucky on those split plastic bushings that you're missing in your oddball split headset.
My Vespa neighbor has the same headset and has wizard home workshop equipment for making things from wood, plastic and metal. He made a couple prototypes from birch and an old plastic cutting board. When he found they worked fine, he knocked out SIX sets so if anybody out there is in need... I also have some other random parts for this weird headset, so if you are needy, just hit me up.