I think you can interpret that many ways. But regardless, does it really matter what fraction of these men were deists? What do we take from it? I'm a non-religious person, and I much appreciate that I am not discriminated against for it in the US. As a student of history, I've found countless examples of Christians killing people. I have encountered plenty of nice Christians, but I've also encountered some very unfriendly ones: racist ones, ones that sabatoge others at work, etc. I haven't found that being a Christian means you are a good person. Yes, Christianity mostly teaches you to be one, but I've found that I act more Christ-like than some people that go to church on Sunday. Morality doesn't require faith, and it surely doesn't require a specific type of faith. We have a system that recognizes this, and I for one am glad for that. Of course everyone of faith is going to think they are coming from the right direction, but that is fundamental property of faith itself. I have no problems with people practicing their faith, or constructing a world-view based on it that's different from my own. But, I become very uncomfortable when a specific faith wants to guide the interactions of those that don't practice it, especially through government. Deists or not, the founders were wise to the dangers that religion can pose upon a pluralistic democracy and tried to keep church and state seperate for it.
Another hint might be from the following statement" Benjamin Franklin signed Pennsylvania's 1776 Constitution, which stated in Frame of Government, Chapter 2, Section 10: "Each member of the legislature, before he takes his seat, shall make and subscribe the following declaration: 'I do believe in one God, the Creator and Governour of the Universe, the Rewarder of the good and Punisher of the wicked, and I do acknowledge the Scriptures of the Old and New Testament to be given by Divine Inspiration.'"