It could potentially be one of the following.
While I'm also thinking rebind, galley and page proofs are pre-release copies of a book for authors and editors to look at prior to the book's publishing. Both the galley proof and page proof are cheaply printed, since they are not intended for public consumption. The difference between the two is the galley proof is intended to be written in. Corrections to the manuscript are made here. The page proof is meant for checking the layout of the book, and at this point authors and editors are discouraged from making changes. This is because changing a plate for a particular page is expensive. Both proofs can have artwork, though artwork is far less common on the galley proof since that proof is specifically for the editing of the text.
In any event, we need to see a picture of some of the inside pages so we can see what's going on here. But, in the unlikely event that it is a proof, even though it may be the only one still in existence galley proofs often aren't as valuable as a true first edition of the same book, simply because of their plain nature.
