yes you can write a gdfs from another fone of the same model. setool box can and does do this well. and if anyone actually had working patches that disabled the otp<>gdfs check then anyone of us could do it by dcu-60 and free soft.
other than this it will brick your phone, but if you have backed up your gdfs it can be written back with setoollite or xs and phone will function perfectly as if nothing ever happened.
ive written gdfs after gdfs to one particular phone and revive it everytime with the backup of the original gdfs.
you can and "SHOULD" make a gdfs back up with xs or setoollite asap, you may find it invaluable one day. as it is the ultimate get out of jail free move for an se cell.