Yes you need to rebuild the lighting if you want the a high quality lighting to be baked and yes there would be a difference between preview and production.
Preview does not cast as many photons for accurate lighting as Production would. Preview is meant to give you an idea of what lighting would look like, but it is far from accurate.
I have some more examples of quality differences between Preview and Production here on our Wiki Lighting Troubleshooting and Tips guide: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums
Here is an example using my scene from earlier:
From top to bottom: Preview, Medium, High, and Production
As you can see with the progression there is more detailed lighting that is transferred across the scene compared to Preview. If you really needed to test I would say use Medium as a base if you’re exporting your game for testing, and then use production later on when you’re finalizing and polishing your final version.
Feel free to ask questions if you get stuck. 