I believe you can remove the app, but the GDR3 funtionality still stays.
I did try and remove the whole update and it caused serious issues on my phone.
My advice : if you have it and it works, leave it.
Thanks. But actually I want to keep GDR3 as I enjoy it quite a lot. But I want to remove the app Preview for Developers. But I'm wondering if it's of any use now.