I haven't the foggiest.
Perhaps there is no standardized training program for the tour guides. I seem to recall, although it is a little hazy, that the tour guide mentioned that being a tour guide was not her full time job; rather, she was intern for the Court and part of her job was giving tours. If this was the case, it might make sense that there isn't a set program for these people--which might lead to slightly different versions of the tour from time to time.
James Madison wrote and spoke many significantly important and revealing things. Here is one just for you:
"The belief in a God All Powerful wise and good, is so essential to the moral order of the World and to the happiness of man, that arguments which enforce it cannot be drawn from too many sources nor adapted with too much solicitude to the different characters and capacities to be impressed with it."*
Nancee
*AMERICA'S God and Country, p. 412