Hood Clip Assembly Bolt, Nut, Washer

[Arlyn Bieber]

The July 1, 1931 Ford Parts Price List book does not list a lock washer for the rear hood clip bolts (P/N A-20276-S1) for the 30-31 Model A. Only a flat washer is listed. This is unusual because nearly all bolts and nuts either had a lock washer or a cotter pin. Could this be an omission or misprint? I also checked other 30-31 Ford Parts Price List and they are all the same, no lock washer. The JS does not go into that much detail so no answer there. Any thoughts guys??