We did several of them in the '80's . Our congo was really keen on them and we have, somehere , lots of pics and videos taken of the tours. As the Secretary it often fell on me to organise the coach arrangements .
The tours were all scripted out . The guides (pioneers who counted their time) followed the script. They varied as their personal knowlege and interest in the subject apart from what was written down for them. We certainly did the Assyrian and Babylonian tour , probably twice over. If the museum had a sign on and exhibit that showed anything different from the script, I am sure they would just have said something like "Of course we know better" and leave it at that. Anyway the group could not all get close enough to read the small information signs provided by the museum.
As it happened, the last time we went we thought that we did catch out the guide on something he said, but we were too polite to say so in those days.
Having said that, It was an enjoyable day, if tiring, since you seem to walk miles along the corridors of the museum. The building is a sight in itself.
I went down year on my own for a visit. I hoped to run into the tours and ,this time, ask one or two thoughtful questions, but alas - on that day there were none to be found