Does anyone know if I will require the 2004 LT disks when I try and upgrade.  The disks I we had are no where to be found and we don't want to spend the extra cash on the full version unless we have to.

I don't think you'll need the disks, just the old serial number.

Another alternative is to contact the agent who sold you the 2004 LT package, they can then ensure that you get your original serial number. I also think that you are issued with a new serial number with the new LT package