Not even sure if this can be done with a script. A client send me an ID book in version 5.5. She set up her margins so that there would be extra space at the spine, but she didn't bother to set up her master pages in a two page spread so that her margins would be mirrored. What we need to do is move everything on each recto page (each page has at least two text frames in columns, plus call-out boxes with a separate floating text frame inside, sometimes photos, sometimes headings, all in separate frames) a quarter of an inch to the right. So, everything on the page has to be selected and moved, but only the recto pages. It could be done manually, but I don't know if she is able to do it.