On this parts fiche the Bolt is the most specified component.
The most reasonably priced component used on the Gsf1200 2000 (y) (e02 E04 E18 E22 E24 E25 E34) Steering Stem (gsf1200t/v/w/x/st/sv/sw/sx) is the Nut.
The Steering Stem (gsf1200t/v/w/x/st/sv/sw/sx) assembly is constructed from several parts from which the Stem,steering is the most expensive.