The lowest price component in this Upper Casing parts-list fiche is the Washer, Plain (663).
The 30g 1988 Upper Casing consists of fourteen pieces with the Casing, Upper being the most expensive.
With all the components that make up the 30G 1988 UPPER CASING assembly. The Bolt, With Washer(6j8) is the most frequently specified with six applications.