Hi Jim,
Sorry no is the answer there. However, if you look at the main pic behind the passenger seat on the RHS is a small bracket with a pin on it. Could this be the means they were affixed by? I can see the outline of something similar under the magazines that are mounted. I don't know whether the Lewis magazine had a small central opening or not, but if it did that might be one answer, other wise this could be a home made method for display purposes but either way they must have sat on some kind of clip or pin affair.
Perhaps someone else knows or I can ask them next year.
Cheers
Al