Using dd, you can save a copy of the GRUB code to a file or to a zone of the raw disk. Be aware, however, that GRUB gets "hard-coded" to point to the location of its files in /boot/grub. If this relationship changes, then the relocated code will not work.
To copy the MBR portion of GRUB to a file:
(assumes SCSI/SATA drives, GRUB on first drive.)
dd if=/dev/sda of=/path/to/grubfile bs=446 count=1
"/path/to/grubfile" could be--eg--/home/username/grubfile
To copy to the boot sector of a partition (#2):
dd if=/dev/sda of=/dev/sda1 bs=446 count=1
See the booting link below for more info.