Are the Removable Hard Drive mounts universal? As far as being able to swap different mounts with holders, as long as you keep the same drive type (IDE, SCSI, etc)? Just curious. We have some units that use portable hard drives, but I have no idea who makes the mounts to get matching ones. Being able to take the drive out of the DVR and put it into a computer to get at the files would be a big help, but if I need the same make if drive bay, I have to know that. Thanks