[CentOS] *very* ugly mdadm issue

We have a machine that's a distro mirror - a *lot* of data, not just
CentOS. We had the data on /dev/sdc. I added another drive, /dev/sdd, and
created that as /dev/md4, with --missing, made an ext4 filesystem on it,
and rsync'd everything from /dev/sdc.

Note that we did this on *raw*, unpartitioned drives (not my idea). I then
umounted /dev/sdc, and mounted /dev/md4, and it looked fine; I added
/dev/sdc to /dev/md4, and it started rebuilding.

Then I was told to reboot it, right after the rebuild started. I don't
know if that was the problem. At any rate, it came back up... and /dev/sdc
is on as /dev/md127, and no /dev/md4, nothing in /etc/mdadm.conf, and, oh,
yes, mdadm -A /dev/md4 /dev/sdd
mdadm: Cannot assemble mbr metadata on /dev/sdd
mdadm: /dev/sdd has no superblock - assembly aborted

Oh, and
mdadm -E /dev/sdd
/dev/sdd:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)

ee? A quick google says that indicates a legacy MBR, followed by an EFI....

I *REALLY* don't want to loose all that data. Any ideas?

         mark