On the ps2 and 3 you can't only on the ps1
Something about the game using the random number generator (which uses the clock as part of it) on the ps1 to decide if you can get a gold one, because the ps2/3 don't have this number generator (not sure about the details) it only relies on the timer so when said timer reaches 99:99:99, whatever number it generates, you won't get a G-chocobo. So just get all of yours before you max out the time and you'll be fine.








