I tried doing that and my phone is still not restoring. The bar gets about 2/3 of the way and freezes.
This is what I wrote on another post, might be helpful:
Google iOS 6.1.3 Download, (or iOS 6.1.4) and download the ISPW from the internet. Then ALT+Click restore on iTunes, select the ISPW and done.
Would I be able to restore from an iOS 6 back up I have a lot of stuff I don't wanna lose and backed up before jumping to iOS 7
iOS7 is a beta and you shouldn't install it on a device you use as a daily driver as it may go kaput.
The recommended setup is having a separate testing device to your main device.
After you finish the restore, it will prompt the usual "Set up as a new iPhone | Restore from Back Up" options.