The original 60 and 61 switches are not the same as later models. They have a sort os semi half moon in chrome which patially surrounds the head of the key. I can't speak for later than 61 models, but the reason that these are shaped this way is for a special feature which doesn't have a Chevrolet name attached to it, but could be called a farmer's switch or construction switch. The feature was that you could start the truck with out the ignition key, if the switch was left in the proper position. We'll call it position 2. So, position 1 is "off and locked". Position 2 is "off and unlocked". Position 3 is "Start". So basically, if you were on the farm where no one was around, AND, you didn't lock the switch off into pos. 1, you could start and run that truck forever without having they. So could your farmhands, your kid, or your workers. Savvy?
So back to the switch, the chrome half rounded part was for leverage for your fat little fingers to actually turn the ignition switch without the key.
