I don't think GPT and EFI are adopted in Ubuntu and Fedora.
There are several ways to identify a partition and Linux can use any one. If you install Ubuntu you will find its /dev/disk has the following choices
Code:
root@saikee-desktop:/home/saikee# ls -l /dev/disk
total 0
drwxr-xr-x 2 root root 680 2007-08-19 16:45 by-id
drwxr-xr-x 2 root root 180 2007-08-19 16:45 by-label
drwxr-xr-x 2 root root 700 2007-08-19 16:45 by-path
drwxr-xr-x 2 root root 540 2007-08-19 16:45 by-uuid
root@saikee-desktop:/home/saikee#
Due to the realignment of the Pata disk with SCSI/Sata/USB disk Ubuntu is now adopting the by-uuid method which has similar device names as GPT's guid.
Linux does not change the current PC standard on hard disk. The uuid name is automatically generated when a filing system is created in a partition inside Linux.