How to confirm hard drive ufsid before upgrade?

[Tigger]

Hello. I recently upgraded 7 remote servers from FreeBSD 7.2 to 8.0.
During the process, 3 servers had hard drive ufsid issues. Basically
during the reboot between 7.2 to 8.0, the drive ids 'changed'. 

I'm using ufsids in fstab.

All servers have two SCSI drives, but have all been set-up by different
people that have come from a Linux background. I can only assume they
have used different commands and methods to format the drives.

I'm assuming this issue is related to GEOM_ changes, however it is not
very clear how to prevent this from happening (I'm sure I'm missing
something).

I have one more machine to go which is a lot more critical than the
others and do not wish to have this one down for as long as the others
where. It took about 6 hours to get the tech guys at the other end to
get 2 of the boxes back up, the other one was easy to get up, but all
data was 'lost' on one drive and had to be restored from a back-up.

-Tig