The strange visitor (me) from another planet (USA, circa 1950) showed up at the auto parts store looking for the little wire clips that hold the bullet connectors in the brake light switch. It's no surprise when the kid in his twenties has never heard of the product. But when the middle aged guy has never heard of it, you know you're wasting your time shopping for it. In this case the answer was to make them out of paper clips.
I think what you were looking for is a called a hitch pin clip or a hairpin cotter.
http://www.fastenal.com/web/search/product/fasteners/pins/hairpin-cotter-pins/_/ Navigation?searchterm=&sortby=webrank&sortdir=descending&searchmode=&refine=~%7C categoryl1:%22600000%20Fasteners%22%7C~%20~%7Ccategoryl2:%22600108%20Pins%22%7C~ %20~%7Ccategoryl3:%22600114%20Hairpin%20Cotter%20Pins%22%7C~
Should be able to find them at a hardware store, auto parts store, farm and fleet, Menards, etc.
Steff Jeff:
I have bought hitch pins for Center Door passenger seats at ACE Hardware.
Yes, those will work, but they're not the same as the original product. My version is pretty close.
Steve,
I found this clip available online, probably at better fastener stores, too.
Go to Clips and Fasteners for more information.
For what he's got he's made exactly what he needs. All I'd do is heat them with a cigarette lighter or little torch then quench them in oil so they'll have a little temper.
I'd go to a parts store and buy a stoplight switch for most any '67 or earlier car but with spade connectors, or just buy a new stop light switch, they come with the clips, if it has that style connectors.