The five Trx300 Fourtrax 300 1988 (j) Usa Marks component parts are all listed in this schematic.
On this parts fiche the Mark,side*type 1* is the most specified component.
A sample from the products for the Marks include: Emblem,r.*type 1*, Mark,side*type 1*, Emblem,l.*type 1*, Mark,fr.f*type 1*.