Will un-rooting return stock apps I've recently rooted my phone - mainly to remove a bunch of the stock apps that I never use, e.g:


Google+
Google NewStand
FM Radio
Google Books


I'm wondering, can I now un-root my phone, and if so will this leave these off my device? Or will un-rooting return them back to my phone?
Yes.

You can unroot your phone. Use the method that GUI app (SuperSU, Superuser etc.) you use offer you to do it.

No.

It won't bring those apps back. Rooting is just a process of adding a binary in the /system partition that will let the apps approved by the GUI app execute commands as the root user, a user that is not an object to the standard rules other users are. This process is completely unrelated to the presence of the stock apps (assuming what you mean by it are the apps sit in /system/app directory of the phone) If these apps are deleted then the only way to get them back is to install them again. If you want them to be stock apps again you need to move them (or install them in the first place) to /system/app directory.