Generally, manufacturing issues/defects like this usually lower the grade of the book and are negative factors on the value.

There are some exceptions, but they are few and far between, and typically involve a significant error or misprint.

One such exception is the Dungeon Masters Guide, Second Alpha printing, which you can read about here:

Dungeon Masters Guide

That's a nice printing to have since it's the resulting product from the 2nd Alpha recall.  It's rather humorous that it has a stitching issue, too, but it's not surprising because the quality of the reworked books was not great.