There are other books making different claims as you know.
Yes and I have proven that they are wrong. The one book you hold onto in particular that has Brown commentary that he makes no mention of any defensive armament & has a cutaway drawing with guns that he did not draw. I have found every AR-234B that Brown was involved with and have photos of all of them & none have rear facing guns.
The book that is quoted above was printed in 2015 not 30 or more years ago.
So find me the ones he flew or had anything to do with that had rear guns. You already contacted the National Air and Space Museum at the Smithsonian.
They gave you the same letter that I have.
What do you know that a museum of that stature has wrong?