Roger,
If it was, I think it was probably mentioned, but not really gone into to. The presenter was more interested in trying to prove that Lincoln was a Christian, which I think is a major problem with many books on Lincoln, although I also think that some authors try to go too far to show that Lincoln was an atheist. I agree with Richard that Lincoln was likely a Deist and while not questioning the existence of God, did question his purpose.
William Barton didn't believe that Lincoln wrote the pamphlet in question, but that Hill actually burned a letter Hill had written about Ann Rutledge, although his reasoning is as circuitous as he alleges Herndon's and James H. Matheny's to be. Barton, a Congregationalist minister, clearly shows his own bias in
The Soul of Abraham Lincoln.
In 2011 I presented a paper at the Conference on Illinois History exploring James G. Randall's "Blundering Generation" thesis and how his Methodism influenced his views. The moderator for the panel was
Stewart Winger, a professor at Illinois State University, and the author of
Lincoln, Religion, and Romantic Cultural Politics. I wanted to talk with him about Lincoln's views on religion, but didn't get the chance as my panel was just before the Thursday luncheon. I've owned his book since it came out, but I haven't had time to read it. Hopefully some day.
Best
Rob