Hi Deagol,
Yes, the books have the same thickness and numbers of pages. Even the boards are the same, concerning thickness and structure.
Would be very interesting if other copies survived...

Is it missing the map? - removed or never there?

There was a map glued in but unfortunately it's missing...

Whoa! Some of you have really amazing items. Mine don’t come close...

My favourite item that I spent almost a decade tracking down was the Weta Workshop Press Kit that Weta has released around 2003 showcasing all their work on the LOTR movies and, to a lesser degree, the other movies they’d worked on until then. The DVD came with a lovely book and call out cards that showed the breadth of skills Weta brought to the films they worked on. I had only ever seen one of these come up for sale in the decade I searched for it. And I’ve never seen one come for sale after.

My favourite book would be the 1979 Pictures by JRR Tolkien. I got one in really
good condition, including the slipcase, and it was a delight to pore over it when it was the only book about Tolkien’s works that I had.