Yes, they should be combined. To help the librarians see that it is the same book, you can put a short explanation in the box that comes up under the request. I usually put something like "originally published as by Jane Doe, rereleased as by Mary Smith" or something similar. If you have a link that confirms it from the author's or publisher's website, it wouldn't hurt to include that as well.
Thanks Ripley, the author herself said it on her website so I'll just add the link to that in the box.