What is the quip?
It’s somewhat quick and subtle but during the opening narration when he discusses the reasons for fighting(”those who call God by different names.”) which contrasts with what Peter said concerning Jesus Christ in Acts 4:12-”Neither is there salvation in any other: for there is no other name under heaven given among men, whereby we must be saved”. Consequently, I would not say Christians and Mohammedans(and other non-Christians) serve the same God by different names. Nevertheless, as both a Bible-believing Christian and a freedom-loving American I would support the liberties of non-Christians to disagree with me about it, i.e., I wouldn’t try to deprive them of their property, life and freedom over this topic and would expect them to show me and fellow believers who agree with me the same courtesy.
On the topic of the film, have you seen it? It’s quite entertaining and I believe it was a huge hit. I read that director J. Lee Thompson’s work on it prompted his hiring to be the director of another subsequent classic adventure hit, “The Guns of Navarone.”