There are essentially no graphical elements in The Book. So no overlap is possible. There are 16 tables, which are graphical elements in the publishers terms, but are not what we normally think of as graphic objects.
but in practical terms, none is possible.
I don't mean *graphics,* like charts and pictures and tables and whatnot. I mean things like fonts and colors. They have more of an impact than you think. Or a logo (which I doubt you have). Also things like -- and I don't know if you have this -- but if each page has a flush-left header with a 2-point rule under it, that can be repeated. If the page numbers are centered, that can be repeated. It might sound silly, but it ties different products together.
And if it's just plain naked text set in 12-point Times New Roman with no headers, not much of anything, well, then you can look at that as free rein to create the supplement. Surely the cover has something more distinctive than just 30-point Times New Roman text on a white background?
t edit And you might not want to tie them together. I'm just rattling off stuff I generally do. I'm certainly not an ace designer, so you'll be better off talking to a someone who is about all your stuff.