It's true. But not the convention you're thinking of. It's Ron Paul's counter convention for those that really believe in limited government, as opposed to the mainstream Republicans who only offer lip service.
Ron Paul's wife has been sick, and he was speaking of those that have sent him well wishes. He says that he was delighted to receive these notes, and they came not just from Christians and Jews, but also Muslims. Lo and behold he also got them from agnostics and atheists and he was delighted to receive those as well. Listen to this brief segment here or the entire speech here. The atheism statement is at about the 15 minute mark.