SATA controller mode RAID?

HP Pavilion Desktop

Model  a6120n

Product GC670AA-ABA

Hitachi HDT725 hard drive

I am servicing the above computer for a friend.  It has a single Hitachi HDT725 hard disk, but the BIOS "SATA controller mode" is set to "RAID" instead of "AHCI".

Questions:

1) Is this the correct setting for this Model?   If so, why?  Why is it not set to AHCI??

2) I have a Linux boot USB with an app that I use to access hard disk S.M.A.R.T.  info and commands.  Can I use that on this machine?

Thank you.