Sorry, that's the exact same question you already asked but my answer wasn't clear. The answer is "yes" because I previously said "entire PDS".
The SFTP backup allows you to create a system or a data backup. If you make a data backup, it cherry picks the DB files from the PDS area and exports unixware config from the Assistant. With a data backup you can restore your config but the V5.x.x. etc would remain unchanged. If you make a system backup, you get the complete PDS and unixware install files too, which would include all versions etc.
The PDS area is the boot area of the RMX OS, it contains the operating system, the DB, the patches, the loadware for the peripheral cards.. everything for the phones to work. PDS and all the other ancillary areas, pas, gla, cgd, scr etc sit in a (1.3GB from memory?) partition at the start of the HD. The Assistant uses three other partitions, Unix boot, base, installation. If you examined a 4K HD in a partition editor, fdisk etc, you'll see those four partitions...RMX will be first with type unknown/other, then the three Unix partitions. The editor won't see the PDS and other RMX areas because they sit inside that initial unknown partition, but it does see that inital partition. That's why the RMX and Assistant are treated separately, it's two OS's running on the same HD. Processor timeslices between them. If you lose the Assistant partitions, the phones don't care, the RMX will continue to run from PDS. If you remove the HD from a booted 4K, RMX doesn't need a running filesystem and so phones continue to work but Assistant would fail because it (unixware) needs the HD. RMX is very stable, it boots first from PDS and then it will try and boot the unixware once the PDS is loaded. If the unixware partitions are missing, and the Assistant install files are available on the SCR area, it will try to install the Assistant. If it fails it will give up on Assistant but RMX is already loaded and doesn't need Assistant to run, so phones will be working.
Above is true for V5 and earler. From V6 and later, the architecture is different. Same building blocks but put together differently.