On this parts fiche the Bolt is the most specified component.
A sample from the products for the Handle Lever include: Cable Assy,throttle No.1, Screw, Cable Assy,throttle No.2, Rnocker.
The most reasonably priced component used on the Gsf1200s Bandit 1999 (x) Usa (e03) Handle Lever is the Screw.