And as for the version issue, the question is: did the mount tool change in the newer versions? Because the mount is such a basic operation, I don't think it has been changed. As far as the IDE / PATA harddrives are concerned, I estimate the mount is the same in the most recent version of FreeBSD. Using a newer version would be a waste of time, actually.
Yes, a lot of details have changed, especially for administration of machines. For example, the old
ad(4) disk driver doesn’t exist anymore, it has been replaced and is now integrated into the CAM framework, which means that device nodes have different names (things like
/dev/ad* don’t exist anymore). This affects mount commands, of course. It also means that you now use
camcontrol(8) for IDE / ATA drives (formerly it was only used for SCSI drives). There were a lot of changes to the GEOM framework, too, so now you can consistently use
gpart(8) to manage partitions, while the old
fdisk(8) and
bsdlabel(8) (formerly known as
disklabel(8)) are deprecated and don’t work correctly anymore. These are just examples from the top of my head; there is much more.