Actually, it's not the center; however, your suggestion to consider the booklet in terms of sheets instead of pages was right on.  Not including the cover, there are four sheets of paper.  The first two use typed numbers and the last two use handwriten numbers, even though not all of the pages have numbers.  The paper used is identical to the paper used in The Dwarven Glory map pages (full size), and is clearly a higher quality than what was used in my POTVQ (black folder).   Just looking at the two side by side, it's clear that more care went into the actual printing of the pages with TDG than with POTVQ, if that means anything.