It is unlikely. When you turn the key it turns a flat rod (a bit like a flat head screwdriver) at the back of the barrel. This turns in a slot on the switch. If you can feel the lock 'click' through positions 1 (no dash lights), position 2 (dash lights on) and position 3 (starter) which is sprung and will return when released. It should be fine. If the switch has been tested it sounds like the wire to the starter solonoid is breaking down or the terminal on the starter is dirty/corroded.