Obviously, they all can't be the word of God since they all contain different words and different truths. God cannot contradict Himself.
I don't get my theology from the thoughts of man in the preface of the KJV, but from the words contained within. Because they did not claim God's hand in translating the Scripture does this mean that God could not be or was not in control of their commission? For the answer we must look to the Bible, our final authority in all matters of faith and practice.
When John the Baptist was accosted by the Levites in John chapter one and asked if he was Elijah (John 1:21) he answered that he was not Elijah. Yet in Matthew chapters 11:7-14 and 17:10-13 Jesus Christ plainly stated that John was Elijah. Did John the Baptist lie? No. Did Jesus Christ lie? Of course not. The answer is very simply that John was Elijah but he didn't know it! Thus we see from our Bible example that a man can have God working through him and not know it. Likewise, God could easily have divinely directed the King James translators without their active knowledge.