Parts such as the Exhaust: Plate, Protector, Nut(2uj), Bolt(4kb), Pipe, Exhaust 1 are included in the Yfm350fwbl/fwblc 1999 Usa Except California California Exhaust parts fiche.
In this schematic the "Bolt, Button Head" is used most often.
Of all the components used in this assembly the Muffler 1 is the most expensive.