I have a Z77X-UD5 with the latest F14 bios, and there is no secure boot. You have to make sure that you boot the install media via UEFI or it will not configure the drive for UEFI.
If your drive is already partitioned, then whether you boot with EFI or not, it won't install a UEFI boot. You basically have to have a clean drive in order to get Windows to convert the drive to a GPT drive, and partition it with the UEFI boot partition and MSR partition.
That means, if you're upgrading, you won't get UEFI support.
If you install and you aren't in UEFI mode (you can find out by running System Information and looking for the BIOS Mode) then it's possible to convert it after the fact, but it's something of a complex process, detailed here:
Moving a Windows 8 legacy installation to UEFI? - Microsoft Community
Unfortunately, Gigabyte's UEFI bios is actually a hybrid BIOS.. it's sort of a UEFI wrapper on top of a normal Award BIOS. This means it doesn't have all the normal UEFU features, like a command shell, or secure boot.
Hopefully the come up with a real UEFI bios soon.