I'm not sure if the SP3 and SP2 are the same in this regard, but I had been using the beta and then did a total system reset and my SP2 reverted to Windows 8.1, then I performed an upgrade to get the free upgrade outside of the Insider beta method, opting to keep no files or settings. After that, I tried the system reset and again reverted to Windows 8.1.
Then I made a bootable Windows 10 Installation USB flash drive and did a clean install. I deleted all existing partitions and when I selected 'create new partition' it automatically created the pre-existing recovery partition, though I'm assuming this time it stores Windows 10 recovery stuff. Between all those upgrades, figuring out the bootable USB drive creation (the Windows 10 Media Creation Tool doesn't work), I'm not up for trying another system reset to find out ;-)
The clean-install itself worked out well, wouldn't accept my Product-ID -- but all the screens requesting it had a 'skip' option. Once it connected to the the internet, it activated on it's own without needing my Product-ID.
Lots of users at the Microsoft Support forums for W10 are posting about issues creating a bootable W10 USB drive using the Microsoft tool -- I used a solution provided by a user and it worked the 1st attempt, after a couple days of trying unsuccessfully with the Windows 10 Media Creation Tool:
Daniel Byrne replied on July 31, 2015
I found a solution.
1. Use Windows Media Creation Tool to download an ISO of Windows 10.
2. To create a bootable USB, use Rufus to create a bootable USB with the windows 10 ISO.
3. Follow this tutorial for more in depth instructions:
http://www.techverse.net/how-to-create-bootable-usb-flash-drive-install-windows-8-1/
This was my solution, hope it helps!
(The tutorial is for 8.1 but effectively the same).