The Brake Cam listed is for models after 1984-onwards. This brake set up you see are for all Drum models Vespa PX/T5. The item screws into the back of the drum, held in place by the Backplate Cam Holder. This is an aftermarket part made by BGM.
Advice: use copper grease where you can! It can make the job taking of nuts bolts & brake shoes easier!
Comparison Part No. 179568 (out of production) (PIAGGIO) BGM9011 (BGM)