It's common for people who have close associations to have events that could be construed as involvement, and when someone does believe they are involved in something important, they tend to claim their involvement was important. It would be so easy to inflate a random conversation or a little common courtesy assistance as something more. It takes some genuine humility to take stock of all your interactions and conclude that you had nothing to do with one of the most important discoveries in history, and more still to admit that you thought nothing of it at the time.